Fiesta RS Turbo will not fit.

Just use standard XR2 shafts, preferably with an ERST (LSD) box, or just use any BC box. With a half-decent clutch, any of the boxes will cope with 200bhp.

I am running a turbo'd track fiesta with serious torque, and never had any issues with using XR2 driveshafts.

Jonboy