Horsepower needed

If you don't care about money just buy a fast car like a new Camero or Vette. You will spend thousands swapping in a slightly larger engine (if possible) and all you will gain is a few measly HP.

FYI both those motors suck.

I had a rare Sunbird convertible with the 3.1 and a 5 speed manual and it was a great little car. Zero problems over 130,000 miles. Only sold it because it was too small for a car seat.

The 3.1 is not a good engine to build for performance, it has too much weight for size of motor, and it is a hot-running motor, in addition it has a terrible intake and head gasket design, it's one of the few out there with a rep for needing to replace intakes due to "metal erosion." It should have been a recall but GM just left it as a TSB: http://www.automotiveforums.com/t550452-intake_manifold_deteoriating_gaskets_problem__gm_service_bulletins.html The 3.1 could spring a coolant leak into the engine with little warning, trying to hotrod one is flirting with disaster. I had one crack at the EGR port, the gasket was fine, the intake was garbage.

Trade it for a Mustang GT.

Always start with a good factory engineered car and make your performance upgrades to that. A 3.1 Pontiac GP/SE is not that car. Bob is right ... except for the Mustang part. Sell your car and find a supercharged GTP. They are relatively inexpensive and go like crazy even without mods. You'll have a car you can actually drive and enjoy.