Originally Posted by GXP Venom
And as stated by Zex, the new systems are no more harmfull to engines as any other type of mod. You just dont want to go beyond the torque limits of the bottom end and tranny. I doubt my nitrous will hurt my tranny given they are now bolting 469 Hp */C 4.4'* to them. Allthough I dont know the bounds of a 4T65.
You've got a 4 speed FWD 4T80-E. The 4.4L */C Northstars are being bolted to a 6 speed RWD 6L80-E. Totally different transmissions.
But, the 4T80-E is MUCH stronger than a 4T65-E. It would be worried about a stock 4T65 with nitrous and a 3.4" pulley. You'd need to have at least a shift kit installed in the 65, if not stronger clutches and an LSD to prevent diff failure.
With those done, I'd think a quality nitrous system would be what you're looking for. I'd recommend away from nitrous because you can do so much other stuff, but it'* your car, so you can make power however you want.