John, the way I understand it, COS 5 is the same as COS 3, plus a couple of extra features, such as the pin 56 stuff. Check here for details.
Oh, and I've had V2 as well as an LC-1 (not installed) for a couple months now. I'm still trying to learn as much as I can before I go tinkering with too much stuff. The most I've done so far is fiddle with a couple not-so-important settings in Rob's C6 vette. Other than that, mostly scanning/logging. Thanks for the gesture though.
After I boost the car, I'll be bugging the crap out of you for info. Hope you don't mind.