.

Cheers for the replies, The only reason I was thinking of using the original callipers is due to the fact I already have them and if there was a simple bigger bolt on disc upgrade it's easy.
I'm trying to keep a factory spec disc for ease of replacements, cost and keeping it simple. they are going on my convert Escort RS Turbo, not going full race spec car or anything like that so wanted an upgrade to match the rear 4x4 brakes I already have.

I do like the look of the E38 callipers and Focus RS disc, the callipers do look very similar to a set of Porsche Brembo's I have already.

Cheers again.