Droppin the H22 in it would probably be the best bet, it's a more common swap, and the parts needed for it are readily available. But it's gonna be a tight fit. tell your fiend to open up a lil room, and gain some extra power, consider losing the A/C. check out enjo for the mounts.
For the frankenstein hybrid, I'm not 100% sure, but I believe you have to swap the head bolts around, requires some machine work.
If you decide to just beef up the B20, make sure you get a reliable head gasket, B20's are notorious for blowing them.
and a lil personal preference, use redline oils, they're proven to free up some free power.
You should check out reace engineering's site, really halpful people <<<raceeng.com>>> tell em BIBO sent ya.