Well, i'm going to talk like you're a newbie.
Any type of forced induction is better off on lower comp pistons. c5 has high compression pistons. You would have to stick new pistons on it before you stick anything more then about 6psi on a 15g (example only). You would also have to get new cams, b/c the itr cams are n/a cams. The tranny is also for n/a, it has shorter gears, not the best for boost. It is also VTEC. Read pissedoffsol's post around here somewhere. He lists a GSR/t and LS/t. How the GSR put down more power on the dyno, but ran slower in the 1/4 mile.
For the money of an itr, you could have gotten an LS and started your way to boosting.
If you spend the 5k or so for an itr, you will be selling. The header, tranny, cams, and pistons.
Get an LS swap for 1200-1500 and have everything you need, then you can decide, rebuild the internals for more boost, or boost stock. Either way, you should beat a n/a itr.