Someday I'll learn the new chassis codes. I'm assuming since he mentioned '01 ITR that he was refering to the older Integra style chassis. I just know EF/EG/EK/DA/DC and use those, I don't know the specific model numbers.

If you stay away from the higher level track cams, you can actually get pretty good performance on the street with an correctly designed cams. As far as I know, the Skunk2 stage 1 and stage 2 cams both have very useable powerbands. I was actually looking into a set for my '92 CX/B18C1 hybrid before it was smashed. I'd recommend a valvetrain upgrade with any upgrade but I've heard and seen dyno plots of good numbers from Skunk2's stuff.

I don't know if I'd spend the money for the ITR head or not. For what your going to pay to get it, you'd probably be better off with some porting work on your GS-R head and a good valve job. With Skunk2 making the ITR manifold knockoff, you also have a good manifold to upgrade to as well. A lot of people who I've talked to who have upgraded have been happy with it. I'm not really sold on TB upgrades, I haven't really seen verifyable numbers associated with them (usually installed with other modifications so don't know what difference the TB itself made) but for the money, it's probably worthwhile.