mk3 xr3i and s1 brakes are the same mk4 xr3i and s2 brakes are NOT the same, the s2 uses the brakes off a xr4i or xr4x4 iirc
out of all your choices above id wouldnt bother with any of them and instead
would use
cossie 2wd 4 pot calipers
4x4 discs
2wd pads
you will need to modify the calipers very slightly but it will give u good brakes for little cash, also refurbish whatever calipers you buy with new seals
i have s2 brakes on my s1 and as the s1 has no abs they work well
Why would you use 4x4 disc's when 2wd ones are bigger and will work with that set up????!!!