Hi
I know where your coming from as I spent 2 months in Spain working before Christmas and am now struggling to get started again
I think that the engineers at Ford know more than me!! so when they were looking at fitting a Turbo to the focus they ditched all of the ST170 stuff and went back to using the mtx gearbox with a solid flywheel, fitted heavy duty clutch and drive shafts and an ecu to cope so I would assume that's the way to go.
Luckily mine is a standard 2 litre so its been easy to fit the standard RS bits, drive shafts, hubs, brakes and front suspension, I will be using the standard inlet but with RS injectors Omex ecu and RS manifold and turbo, yes basically every thing from the RS as that has to be the easiest way.
As I said above Ford did not use the ST170 gearbox and dual mass flywheel for a reason so can a mtx gearbox be fitted or are you sticking with the ST box and flywheel?
As for mine I am waiting for an actuator to arrive (in the post) before fitting the manifold and turbo, then I need to sort out the oil lines and intercooler ( bought a universal front mount to get started) my engine is St170 based with a thick head gasket but I wish now that I had just bought the RS engine. Anyway I will update my thread when I get something done
Keep up the good work and keep the updates coming they might motivate me, you never know