These cars are good for about 3-400k miles, that said theres a few things that should be watched out for. (coming from someone who has owned 2 GTPs over 200k) The coolant elbows, they blow when the engines get older, try to tell if they are new. wheel bearings, ball joints tie rod ends at this milage, see if you can jack it up, play with the wheel left to right movement, bad tie rod, top to bottom bad axle. listen to the super charger see if it sounds like driving over cardboard when the idle changes, if so bad coupler.
I buy sub $1000 cars so I have more issues than most.