since no one wants to help you due to the fact that this can be found on numerous of sites, I'll chime in......

I'm currently running the original skunk2 mani on my gsr right now, the gains are minimal unless you're cam'n such as ITRs for starters. Second, no you will not need new studs because of the gasket. You will however have to go buy some antifreeze/coolant lines, new tb gasket, and something to scrape off the old manifold. Also you may still use the gsr intake (I used it for about a year then finally bought another one). And last this is a 1-2 hour job at the MAX, took me 45min but thats because I've done it numerous of times even with the pro series (which doesn't make a damn difference, H-T shows gains from the new design of 0.000007 hp difference or what not. Does that help? I'll be back later to help answer your questions.

Oh, and also using the s2 mani with the stock p72 equals your car running like garbage, trust me, the p72 was designed for secondaries (2 stage vtec) so by installing a single stage its gonna run funky. A stock p30 will help solve this problem since your car is obd1.