Think red suits the MPS (and I'm no red fan). There was a recent thread about this very subject, do a search, there was a YouTube clip of an M3 being done in white.
What age MPS are you looking for? The older ones are higher road tax which puts off when I was looking to offload the RX8 (couldn't stretch to the later version).
Current -: MW E92 M3 Competition Pack / Qashqai+2 Tekna 1.6dci
Gone -: 370Z GT Roadster; BMW X3 3.0d xdrive M Sport; E46 330i M Sport Coupe; Mazda RX8 231; Nissan 350Z GT Roadster; BMW E90 330d M Sport; BMW E92 335i SE; Maserati 4200; Nissan 350Z; Honda S2000; Astra Coupe Turbo; Ford Probe