As far as damage to the engine goes, it certainly doesn't come from pushing exhaust through a turbine. So, that should eliminate the 2 of 4 cylinders idea right off the bat. I don't think the engine would act well w/ 2 cylinders pumping a turbine, either.
Never hurts to ask.
I don't know much about the zetecs' boost capabilities on a stock fuel system, but I'd be very surprised if it couldn't handle 5 psi.
