The actual hub face (the rotating part with the studs) is the same but the hub carrier is different between xr4x4 and cos 4x4. As stated the bolt holes are further out for the cosworths due to the larger diameter discs.

Jimbo - as for offsets isn't escos something like ET25 and 2wd something like ET38? I could be wrong on these though - someone will know for sure.