The drag kit is a great kit, very complete. I used to have a rev hard kit which is simliar on a b18a1. I think you can find a better price on groupbuycenter.com or else where. As for the bov, blitz is fine. A hks isnt going to work any better, just a different sound. Gas mileage usually decreases depending on how many psi you run. It wont get bad with good tuning, i still got 25+. A bb will spool quicker but with a t3/to4 like in the kit it wont make that much difference. You seem headed in the right direction just read up some more and look into hondata. Hondata is great for tuning, it will get the most out of the setup.