There's no tuning advantage of getting a PCV over a PCIII unless you plan to add the accessories (LCD, SFM, etc, etc). The PCIII though is discontinued these days and the PCV is the only thing available. It basically works the same as a PCIII does if you're already familiar with that.
The Bazzaz is good too, but there are many more tuning centers available for the Power Commander.
I would think the G2 motor would be better in a car as the torque curve is lower in the RPM range. There's a bit more power out of the G2 as well, but the characteristics are more linear. I would expect it to be a better fit for a dirt-tracker.
Great, Always like to hear I'm doing the right thing. Ill keep you posted. Having a Harness cut down now. Wish I would have known about the race harness back when they were available. Thanks for the Info