I'm not as big of a fan of Mario as I used to be, but I did find a very cheap way of making a Mario Kart RC.

Gut out an old wendy's kid's meal toy and twist tie it to your MT.
The picture includes both bodies I gutted, but the one pictured to the right isan't as top heavy as the one on the left and can even do free wheels spins on its front and back,
I have even tied it to my first edition ZZ and it works great on that too!