Apparently I misread or read too fast but ya, 1997 started the 6th generation and that's the year the GTP actually had a supercharger and I believe 2005 was the last year the supercharger appeared on a Grand Prix.
im fairly sure those body styles of grand prix didnt come with superchargers, even the GTP models, so unless they got a supercharged 3.8 out of a later GTP(it would fit, ive seen it done) it isnt a supercharged grand prix, and seeing the amount of money he put into the exterior, i doubt he went through the effort. they didnt start the supercharged GTP until somewheres around 97-98
GTP existed prior to 1997. The GTP model was introduced in 1991.
HOW are you lowered? Cut springs? Lowering springs? coil overs? Did you get a camber adjustment kit when you got lowered? The kits are about as crucial as, oh say.... oxygen.
Why would it matter how he's lowered.
Check you inner tie rods. I think you installed them yourself, correct? Maybe they have started to back out because the locking tab wasn't bent correctly or at all.