[bigwhitecobra]

The upper plenum is worth it, so is the TB. With or without the CAI, but better with the CAI. A shift kit is also a plus. I assume you have an AODE, if so, you may be better off just flashing the computer to firm up the shifts, rather than actually changing the valve body....(not an Automatic guy, so really ask someone else)

With an Auto equiped car, go with 4.10 gears and be done with it. You'll love'em.