I want to change to the 380mm MTM brake kit before I go to the Nürburgring again

I know that BBS CH 10x19 will rub on the RS6 front brake setup (you need to grind slightly on the corners), and I am therefore wondering if anyone have experience with the MTM brakes. If the calipper is any bigger or smaller than the RS6 calipper.
I have been told that the 380mm MTM kit can fit under the stock "18 RS4 MKI wheels, but not to sure on the design of the BBS CH wheels.
thanks for any input