Hi i have ser. 2 rs turbo lsd. i've been looking for a box to take around two hunderd bhp.I seen ser 1 boxes for sale on passsion ford & e-bay.
whats the differance between ser, 1&2 boxes.dose the splines fit the clutch also gearshift, anddriveshafts.

 

Series 1 didn't have a limited slip diff as standard and had a lower final drive ratio (meaning quicker acceleration)

The rear gearbox casing is different because of the different gearbox mounts used, but is only an hours work to swap it over.