gm performance
Seriously, though... some dealers are "mod friendly", and others are not (even if the modded pieces are GM Performance).
If you're willing to invest the cash, a set of LS6 heads and an '02 Z06 cam would liven the car up, as would an LS6 MAF. Other than that, I'm not sure of what else you could use... if you're restricting yourself to only GM pieces, your biggest issues will be exhaust and airbox lid.
Andy

