Sorry for the mixup, yes 2008 Silverado 2WD, V6. (or 2 sets of FWD wires).
I will put a note on the site about the wires, but lots of guys don't order wires because they are getting Shane's wires or making their own, or other situation.
the little o-ring goes on the nose of the stock ignition module plug. the factory style seal that goes down inside the module side connector is not available, but the o-ring does the same job.
the gray wire is an analog input that can be used for MSD pills or other resistor to set the 2-step RPM. The details on that feature are not in the manual yet, but there is a thread on here.
Bob