all things without forced induction will increase torque by only a little bit. Overboring the engine, etc will cost way too much, so i dont know why you wouldnt go with a supercharger. Unlike a turbo which uses exhaust gas exitting the engine, supercharger is always on from the very beginning of the rpm spectrum all the way to redline. for H22a, jackson racing makes superchargers that are emissions legal and very reliable for daily use. Also, it wont cost a fortune like performing major engine mods.