You will probably have issues with the gearbox mate, the ST170 has the 6 Speed box which is a lot shorter than the RS box so your Focus may not have a cut out the inside of the passenger side inner wing for the RS Box to fit. You could keep the 6 Speed getrag box but you will then need to modify the flywheel and clutch as the dual mass fly and clutch setup will not take the power out the RS engine.


You will also need the full engine management loom and ecu etc but that shouldn't be too big a job