I have created a sporty looking tracker. It is almost a C-model of 42006 set, with just like 4 extra parts and PF stuff. C-model idea comes quickly, once you disassemble 42006 set and observe the variety of parts it offers, however it limits the number of functions. Build process was fun and a bit challenging, as a space is a bit of an issue. The final result isn't as much as I expected. While model drives quickly on a carpet and flat surface it didn't perform as good on hard snow (slipping) or a softer one (not much of a torque). Anyway it was fun and no damage has been made, even the battery box on the bottom didn't have a scratch.
Specs: 30 studs in length (including spoiler) 20 studs in width 2 PF L-motors, one motor per tracks side PF IR-receiver V2 Standard BB