JMP

I ground my LC1 installs to the engine block, they seem to read within .1 or .2 of an AFR compared to the lab grade sensors at the dyno I use. The LC1 sensors get mounted in the dump pipe, the dyno sensor is in a clamp in the rear muffler after the cat.

from my research they're AMP Super Seal connectors, info can be found here: http://catalog.tycoelectronics.com/TE/bin/TE.Connect?C=1&M=BYPN&TCPN=4-1437290-1&RQPN=4-1437290-1 They're a pain in the neck to get all the pins lined back up for assembly if you take the connector apart to remove not-required wires.