[surfbeast]

The PI head swap is what you are talking about. The PI " Power Improved" heads came on 99 up gt's. The 96-98 gt's have a poor flowing head design. The new heads allow more air flow into the engine, More HP. Most engines gain about 35+ Hp and more depending on the other Mods. Cost is about 1,200 for the heads and new intake etc... And if you need to have a mech do the work for you it starts at 500 and goes up. Best Mods for the 96 are , Exhaust, Gears, K&N filter. Don't get a cold air intake they are worthless. If you want to skip the heads get a blower. Read the FAQ's and follow the board and you will learn alot!