Apart from the cam chain, the more obvious difference is the intake is at the front of the engine and the exhaust is at the back. Unlike the zetec which is the other way around.

The mazda versions can also come with VVT on the intake unlike the ones ford uses. The engine has huge potential, shame cosworth didn't get around the selling the d-power stage 3 as that was a nice cheap upgrade to 240+bhp, you can still get all the bits to make your own stage 3 mind you.

Why the newer focus ST came the heavier 5pot volvo lump instead of the 2.3 turbo duratec sums up what wrong with todays performance fords , they have all the bits to make a high performance 4x4 focus in the various company part bins instead we get another volvo s40, at least mazda made an effort with their version of the c2 focus.