imho if your not going to make full use of the variable cam timing and inlet which will need the st170 ecu to work then i wouldn't bother with the st170 engine. just drop a tuned 2l zetec in there, straight easy swap as you can keep your standard fuel
system too!!

also if its going to be tracked and get lots of abuse then i'd fit the mtx75 box and shafts from any 2l mk1 focus.