Those 2.0 Sierra DOHCs are great. Mine used to do 45mg on the motorway and they have much more low down torque than the 130bhp Zetec. They lack a bit of power at the top end but I think this can be addressed by changing the exhaust manifold.
Don't forget the Sierra DOHC was also used in the RS2000 with a 16v head on it, - the 8v piston crowns even have the recesses for 16 valves. You also have a timing chain rather than a belt.
Best one to get would be a Sapphire 2000E or a late Ghia 4x4 with leather, air con and an electric sunroof imo.