you really think it was to help warm the car up quicker in the winter?! it would also warm it in the summer as well!!!

it wasnt just the S2 that used them as the Cosworth's also used a watercooled turbo as well.
Dont think Ford would have used watercooled turbo's unless they thought they needed too!!
as i said before oil cooled turbo's have larger oil ways to help with the cooling of the turbo aswell as to lubricate the bearings!