i've always been told the 2.0 zetecs are good for 230bhp at the flywheel, beyond that they would need upgraded internals.
the silvertop zetec is a bit stronger in the bottom end than the blacktop.
ideally if your over 200bhp at flywheel towards 230 it should have upgraded conrod bolts, they are a weak point. apparently they can be changed with the engine in the car by removing the sump but i spoke to a tuner about doing them on mine and he didnt think it would be very easy
