The main gimmick with Speed Racer was the actual car. The Mach 5 had a buttload of gadgets that each had a use in a certain situation. The removeable canopy, the hawk, the traction wheels, the sawblades, etc...
If we get another batch of SR Minimates in the future, we should get a Mach 5 with all (or most) of the add-ons that were in the show.
I know they're planning a regularly-scaled Mach 5 /w 6-inch figure, but we friggin need a Minimate version.