The 97's were the first year of this design, so it is kind of the oddball as far as the gtp's go. There are a few things different on the 97's than 98-03's but as long as your not planning on modding it, it's not a very big deal.
As far as checking the car out, like said above, these transmissions lose 4th gear sometimes, best way to check is to take it up a large hill that will put load on the car in 4th and if you feel a jerking, then its on its way out... Then check plugs and may want to ask if has the original fuel pump or when it was replaced. Also check the s/c by letting it run and listening for almost a popping sound around the snout. The next step would be to take just the s/c belt off and feel for play while turning the pulley back and forth, if there is, its most likely a worn coupler that is only $30 to replace, but if its a 140k stock s/c, you can find a used s/c for around $200.
