if you MUST do a pulley upgrade, buy it from needswings. DO NOT BUY FROM CODE3. others here will tell you about my horrible experiences with them.
get the SL55 intake and modify it. the SL55 intake alone added 25hp to others' SRT6's.
then get the inmmotion tune AFTER you do all your upgrades to yield the most gains.

i don't know if there are any cold air intakes for the C32. sorry.

i don't have a pulley upgrade, and i still pulled on a porsche turbo 4 times. but the SRT6 is lighter in weight than the C32.(and the whole forum is making fun of me right now because i only weigh 135lbs!!! LOL)