hi mate, i've just put a 2.0 into my mk4 fez. 2.0 zetec goes in but you need a fiesta diesel endura box for the starter to fit. Also need a 1.8 flywheel and clutch. You need to fabricate a drivers side mount, but everything else just bolts up.

If you want big power in the future, you need the 2.0 blacktop from a Focus, don't bother with the mondeo silvertop. If your happy for something nippy to drive, a Puma 1.7 engine and gearbox will bolt in with out any thing needing doing. Cheap upgrade for the mk4 is puma 1.7 brakes and suspension too. Get it all cheap off the bay. I went with the 2.0 because I got offered one cheap, but knowing what I know now I would have gone with the 1.7.

The rs turbo engines fit, just need to sort the drivers side mount again and fit the ancillaries. Go with EFi if your doing it mate as the MFi is toss. The RS Turbo box isn't a straight swap, its mountings are different. What a lot of people do is put the diff from a turbo box into a diesel box that has the taller ratios, and then bolt the whole thing in the bay.

If you want 130 - 160bhp go for a 1.7, if you want turbo power built a zetec turbo with a diesel box.

Dangerous Dave