2004 Monte SS supercharged NEED more HP!

I want to put a smaller pulley on. to my knowledge the smallest you can go with out making mods to the oem supercharger is a 2.8" pulley. i would like to get a 3" pulley and on it. what other things should i do before i slap that on?? i want to get about 100 extra HP out of it....but not just by a pulley but thats were i am starting out at...please help

160-180 degree thermostat, headers, free flowing exhaust, cold air induction, pcm. Check out www.3800performance.com, they have all kinds of parts there for your motor.