Magna chager ls2 GTO!

You would change the pulley on the supercharger to one that would spin faster (smaller, I think).

Check with magnacharger first, the PCM would also have to be reprogrammed because of increased air flow. Depending on boost level, you may have to install larger injectors, or increase fuel pressure.

Magnacharger will most likely not warrant anything above the stock pulley, because you may have to go with higher octane fuel, colder plugs, etc. This puts more stress on the engine/drivetrain and will shorten engine life to some degree.

Do not modify the supercharger without talking to magnacharger first. Adding boost without adding fuel via a reprogrammed PCM will cause a lean engine and that can destroy the engine in a very short time.