To the best of my knowledge.....
S1
Crank Driven Honda/Rover Pump (many retro fitted with later BMW electrohydraulic pump kit)
Morgan/Jack Knight Steering Rack
S1.5 (facelift )
BMW Electrohydraulic pump
Morgan/Jack Knight Steering Rack
S2 & S3
BMW Electrohydraulic Pump
BMW Steering Rack
S4 & S5
BMW engine driven Pump
BMW Steering Rack
Simon @ SiFab.co.uk