with the h22 your defintely going to have to rebuild, because the internals are weak. i would recommend not going with the b18c1 because that's where my problem is now...the comp. ratio is high and not great for turbo.
basically like i said before, if you want 300HP you gotta boost it's the only fiscally logical way. i'd go with the b18b up the internals and boost if it was my car.