Had a similar problem with a rather Gucci set of discs I managed to get my hands on that I wanted fitting to my Senna. Long story short the bike went to Pete @ http://www.panda-engineering.co.uk/ and he machined @ 3 mm off each side of the Marchesini, 2.8mm off back of carrier, re machined the carrier holes to correct ‘pattern’ and then @ 2mm off the callipers…..hey presto some awesome brakes on std. callipers……….mmmmm std. callipers maybe some new ones needed, what you think Nelly?