Without sounding like a jerk, I would say you need to work on your M05. I see no reason why the M06 would be faster than a well setup fwd car. (03 or 05). Infact I would be very suprised if the equally well setup 05-06s didn't produce a several tenth difference with the 05 edging the 06.
Most of the time people setup the minis decent And they are very driveable. But there is usually a second a lap or more difference between a well setup car and a car with a great setup.