The M04 seems to me to be a better design than the M06, with the exception of the rounded battery slot.

I had considered getting a RWD Mini after one race where I had qualified on pole with my M05, but got blown off at the start by an M06. The RWD really leaps out of the hole.

Unfortunately, any RWD car without foam tires, Mini or otherwise, is not a fun thing for me to drive, either.