RE: can you put a turbo on a 4 cylinder?
remember there's more to building for a turbo than psi, while that's a big thing since too much psi will tear your engine apart you have to also think about heat. Turbos produce a whole lot of heat, so while 4cyl take less building for psi(most have lower psi than larger motors) they typically can not handle as much heat. Housing size is a big reason for too much heat, though all turbos produce ALOT of heat. Intercoolers are a definite if you want to run much boost at all, also you have to think about things like location of the ambient air intake, heat shielding, oil cooling, etc. There's alot involved. As far as for takeoff speed, if you go with a turbo you'll want a small one as they spool faster, meaning the turbo gets up to speed and provides the boost at a faster rate than a larger, more powerful, turbo, though the small ones won't give you the high topspeed. If you really want lowend torque(this is what gets you going in the lowend, not hp) I say supercharge it, the power is instant, no lag like a turbo has.