Confused

To make it easy to get started on the forum each user gets a small storage allowance to allow them to attach log files, tune files and pictures to their post.  When you have used up that allowance and try to attach a file you will get an error message stating your file is too large to upload.  The way forward is to upload the file to an online drive service and use a share link to the file.  Google Drive and Onedrive are probably the most common free options in western countries so I have done a quick guide on those two here.  
There are many other options such as Dropbox, iCloud, WeTransfer, etc that usually follow a similar process.
How to share a file using Google Drive and Onedrive.mp4

I've had the pleasure of helping a friend with his ECUMaster Classic ECU, and the one very immediate thing that sets it apart from Link is the quality of the software, and the Help.
The ECUMaster Classic software is, in my opinion clunky, unintuitive, and not user friendly at all.
And, the "Help" is practically non-existant.
 
Whilst Link's software does also have its quirks, it's substantially more streamlined and user friendly, and the in-application Help is the very best Help/Documentation I have EVER seen for any product in my 20+ years in the computer/software industry. It's not just a technical reference guide, it teaches you the theory behind the functions too - which, if you're a newbie, is exceptionally beneficial!
 
Whether their newer Black range software is less bad, I don't know, I've not spent the time to investigate this yet.
 
Before you consider Wire-In or Plug-In - have a GOOD long, hard think about all the things you might want the ECU to do - whilst the Plug-In Links are based upon the Xtreme model, each individual vehicle-specific model has varying numbers of inputs & outputs that are exposed to the user - and one of the reasons you pay different prices for each vehicle model based upon this.
Once I'd started to figure out all the cool stuff the Link ECU could do (E-Throttle, Cruise Control, Traction Control, Launch Control etc) I found myself very quickly running out of inputs & outputs, and had to modify my goals based upon what inputs & outputs I had available to me.
If I were picking an ECU again, I'd weigh this up in my choice of whether I have the "short term gain" of having something that plugged into my vehicle loom directly, or the "long term gain" of having the full range of I/O available to me.
This can be negated somewhat by adding I/O via CANBUS devices, such as the Razor - or almost any other manufacturer's PDM - as the Link CANBUS is, I believe, by far the most flexible of all aftermarket ECU manufacturers.
 
This support forum has also been an absolute gold-mine of information - it is now the only forum I still visit on a daily basis - all other forums have been "taken over" by social media, but this is still the best resource. Yes, there's Link related FB groups, but you can't search, you can't upload/share files easily, and there's years of history here, and such a wide variety of questions being asked almost daily.
 
Whilst the likes of Haltech provide phone support (as do Link!) they only really offer this as their only option - you can't ask for support on their own forum! Sometimes though you need feedback from your fellow owners too, and with forum posts you can go away, research, and come back with the next piece of the puzzle, which you lose if you rely only on phone support.

Post your fix so others can benefit in the future if needed. 

An Temp has an inbuilt resistor (fixed 1k for An Temp 3 & 4, selectable OFF, 1k or 10k for An Temp 1 & 2), designed for reading a temperature sensor, An Volt doesn't have a pull up resistor. You can use An Volt inputs as extra temperature inputs, but you need to supply your own external resistor in the wiring loom.

Oh, sorry for the confusion. We tend to use the more British version of english and I suspect a lot of these odd terms come from there.  I basically means "try it and see".  https://dictionary.cambridge.org/dictionary/english/suck-it-and-see
I once used another one I thought was common English when talking to a German colleague "There is more than one way to skin a cat", I have never seen a more confused look on someone's face before.  

look correctly: https://linkecu.com/wp-content/uploads/2020/07/ECUCatalogue.pdf
"† Check specific pinout for number of I/Os exposed"
the point of plugin ECU is also to have affordable ecu when the car doesn't need all the I/O, because the price of them is also related to that.
for older cars with little I/o need, it would make no sens to only offer a version with all the I/O possible from processor, at double the cost of the actual product.

I would sell your current gauges and sensors to someone who doesn't yet want to use a decent ECU, and instead have a bank of gauges, and you can use that money instead to put known sensors directly into the ECU, and get all the advantages of the ECU to perform protection strategies, and then maybe a single CAN gauge to flash up when there's any errors and the ECU has stepped in - this will be far better in my opinion than having a bank of gauges you're not looking at when you're pressing on, and can't react as quickly as the ECU can.

In most cases error 54 will be a failed/contaminated/poisoned sensor. 
A quick explanation of how a wideband sensor works may help understand the terms "pump current" etc:
The main sensing part inside a wideband sensor is basically the same as you will find in a narrowband sensor, it is a ceramic material with a catalyst that generates a voltage relative to O2 content - but in both narrowband and wideband sensors this "Nernst Cell" is only accurate when the gas in the measurement cell is very close to stoichiometric - not useful on its own for wideband measurement.    So, for a wideband sensor they add an "O2 pump" to the side of the sensing cell, the controller then pumps extra O2 ions into or out of the sense chamber to maintain λ=1 inside the sense chamber at all times.    How much O2 the pump has to pump in or out of the chamber is directly related to the O2 content of the exhaust gas, the reported Lambda value that you see on the laptop screen is determined from the pump current that was required to keep the gas in the sense cell at stoich.  
"Excessive Pump Current" means the O2 pump is pumping as much O2 in or out of the chamber as it can, but the gas inside is not reaching stoich.  
If it is some sort of contamination, sometimes you can recover them by setting "Run when stalled" to yes and leave it powered up without the engine running for half an hour or so.  

Regardless of what you buy getting the signal into the ECU via CAN is far better than via an analog signal so aim to buy something that is CAN capable. The Link CAN is very configurable and so can be setup to work with almost any CAN based Lambda device.
I have seen cheaper Lambda devices be a bit laggy and any analog based signal is prone to ground offset issues and lack of resolution.

The Help within PC Link is VERY good, so that's a good place to start, a lot of concepts are explained here, and in context with the ECU you're using, which is useful!
 
Also, there's resources like High Performance Academy and Evans Performance Academy which are more "structured" training via online videos, webinars and courses.

Yeah, there are not too many easy options with AWD systems like the Evo.  For straight-line type racing or launching it is more common to do some sort of open loop power management based on some predetermined curve of maximum possible wheel speed acceleration vs time or speed. 
I have seen LIDAR or RADAR and even fifth wheels used in some applications.  
The G5 would likely be able to do closer to traditional slip based TC using its "GPS".  The G5 uses a high speed GPS with sensor fusion and dead-reckoning which should remove most of the typical lag from GPS reported speed (not fully implemented or tested yet).   

I'm not a Link employee, so my responses here have no bearing really, but from my experiences, I feel the need to respond on at least some of them!
 
1. Closed Loop Lambda has quite a few calibration & configuration options, so it's likely that you just haven't found the right settings yet for the specific vehicle. Distance of the sensor from the combustion chamber makes a difference at a variety of engine speeds, which is why you have the Update Rate Table, and then you can also determine how aggressive you want the correction to be based upon how far away from target it is with the Gain Control Table. That said, it is also designed to maintain small corrections to an already tuned fuel table, not be a substitute for tuning.
4. Like Closed Loop Lambda, Closed Loop Boost is designed to supplement an already tuned Open Loop boost table. Once this is tuned correctly, you should simply need to adjust your Target Boost value, and the closed loop will adjust based upon minor fluctuations.
 
Maybe you're expecting the ECU to do a large part of your job as a tuner?
That said, it does have tools to aid you here, as one example, there's Quick Tune, which can be used in conjunction with a steady state dyno to fill in your fuel table, and Quick Trim/Mixture Map which can use values from a log file to amend the fuel table.

The plug-in ECU is cheaper than the wire in because it has fewer inputs and outputs available, despite being based upon an Xtreme.
So - you'll need to have a close look at the available inputs and outputs, and see if your current (and future!) requirements are covered.
That's a trade-off only you can consider.
I ran out of inputs and outputs on my Evo 1-3 running a 6A13TT engine from a Legnum VR-4...

The Slip calculation for Traction Control needs to see a difference between Driving (powered) and Driven (unpowered) speed sources, to determine when to cut power...
From the Help, your options for speed sources are:
LF Wheel Speed RF Wheel Speed LR Wheel Speed RR Wheel Speed Average Front Speed Average Rear Speed Min Front Speed Max Front Speed Min Rear Speed Max Rear Speed Average Four Wheels GP Speed 1 GP Speed 2 GP Speed 3 GP Speed 4 Outside Front Speed Outside Rear Speed GPS Speed With 4 Driving (powered) wheels, though, the faster wheel could be either front OR rear, left OR right, so none of those are really suitable for finding an "obvious" way of determining slip - unless you can find a GPS Speed sensor which reacts quickly enough - a fast-acting 100-200Hz one is pretty expensive though!
 
Your gearbox speed sensor is essentially "Average Four Wheels" - so not sure that this will gain you much... but maybe there's something I've missed!
 
I've also got a 4WD Mitsubishi - a Legnum VR-4, this has some form of Traction Control - so someone out there somewhere has figured out a way of doing it with just 4 wheel speed sensors, gearbox speed sensor and maybe the accelerometers from the AYC/ASC system...

A man with one watch always knows what time it is. A man with two watches is never sure.
I think you need to confirm the manifold pressure with another known good gauge/sensor, so that you can eliminate (or confirm) your findings.
You can also record in the logs MGP (Manifold Gauge Pressure) parameter and switch the display units to match your physical gauge(s) so that you can more easily compare.
If you share a copy of the tune and a PC Log (with all parameters defined) where this issue occurs, this will help us narrow down the issue better than just a screenshot of what you think is appropriate

You would generally gather data on what values are not knock, and then in a controlled environment, introduce knock and see what the values show. Your threshold is then somewhere between these two values.

Simplest way is to go for a quick 2 minute drive, with logging enabled, and work through every gear and back to a stop.
 
Then look at the Gear Calc parameter, you'll see the distinct unique values.

@Vaughan I finally got round to setting the updated table breakpoints, and it is now detecting 0 = ON and everything else = OFF for the Traction Disable - thank you, I can now make it work logically to me - 0 is least traction control, 10 is most traction control

Excel file attached.  Note it is simplified compared to the ecu, it doesnt consider fuel temp or the charge cooling effects of the fuel, fuel press etc, but it will give pretty similar values in most cases. 
 
Injection Calcs.xlsx

How have you provided power to the CAN Lambda module?
 
Have you tried installing the 22uF capacitor as suggested in the Alternative wiring diagram. A 16 error is often power supply issue.
 

Apologies for not upgrading straight to the newest Firmware... I've had bad luck in a previous Job role doing that with other equipment.. stuck in my old ways I guess.
I managed to downgrade to the 5.1 Firmware and it started up perfectly and acted how it normally does. Log Attached (5.1.1 StartupLog)
Upgraded to 5.6.8 - started up perfectly, throttle would hesitate and try to stall the engine.
Once I looked at the log I took a look to see if there was anything noticeably different to the 5.1.1 Log - I found that the TPS Sensor was sitting at 0% the entire time. Log Attached (5.6.8 StartupLog)
Did a TPS Cal and I finally have my car back to how she was, so stoked. Log Attached (5.6.8 AfterTPSCal)
It was kind of nice to see a piece of equipment happily take Old and New Firmware versions and not brick on me. I'm very happy.
Thanks to the both of you for your input! It's very much appreciated
5.6.8 StartupLog.llg 5.1.1 StartupLog.llg 5.6.8 AfterTPSCal.llg 5.6.8 MAP.pclr

I believe that all Digital Inputs on G4X (and I assume G5) are capable of high speed input (10,000 Hz range) so this is probably why it doesn't specifically state it in the manual any more, like it did for G4+ and before.

I believe that all Digital Inputs on G4X (and I assume G5) are capable of high speed input (10,000 Hz range) so this is probably why it doesn't specifically state it in the manual any more, like it did for G4+ and before.

The "why" is because it's marginally easier for them to have a single analog pin than figure out how CANBUS works, it's a relatively new technology (introduced about 20 years ago), so many "tuners" haven't heard of it or know how use it
When CANBUS is available for anything, especially lambda, this is substantially better - the controller has the data digitally, why would you want to convert it to a 0-5v output to then convert it back to digital data - it's an unnecessary conversion, and one that's liable to interference and offsets, causing inaccuracies.
Wire it to CANBUS, and be safer in the knowledge that what the controller/gauge is reporting is what the ECU is seeing.

The very latest G4X firmware (released only in the last couple of days) can reassign Ignition and Injector outputs, so that you can get around the previous limitation of needing to use Injector 1-x and Ignition 1-x outputs in sequence. This mean that some boards, such as the Evo 1-3, which had hardware on Ign4, could not be set up for sequential ignition, as you had to use Ign1-4, but with the new firmware, you could use Ign 1, 2, 3 and 5.
 
However, for almost every other output - unused Ignition and Injector drivers, and most Aux outputs (other than those which have specific hardware on the vehicle-specific board, or are "dedicated", such as Aux 5-8 for an idle stepper motor), it is otherwise completely customisable as to what function is used on which pin.
 
As for G4+ vs G4X - G4+ hasn't been sold for a few years now, so unless you're getting one for a very good price compared to a new G4X...
 
But, if you're happy with re-pinning an ECU connector, and "losing" the ability to quickly swap back to stock ECU (however, why would you, once you've got a Link installed) - even a G4+ is still a great ECU, even if for a different vehicle - but the G4X is better.
 
Just have a good look at what inputs & outputs are available, and make sure you'll have enough on the main header + expansions for your needs, and consider fun things you might want to do in the future... I found myself rapidly running out of inputs!