hey man, a supercharger would be the best way to go. Try checking out SLP Performance Engineering.
www.slpeng.com i think thats what it is. If they're prices arent good enough go out and buy a copy of high performance pontiac magazine and check out the adds in there.
As for mods other than a supercharger, a k&n FIPK system is golden, if you have an automatic tranny maybe a shift kit, headers, chip, there are so many posibilites.
Even a fuel injected crate motor!
Later