Hmmm... after getting one of each US color I'd get an additional Iron Man for use as a rally beast. It'd get the following:
Entire drivetrain removed and replaced by custom double a-arm suspension at all four corners with coilovers. A turboshaft engine would be under the hood driving a high-output DC genset. Coupled with a FADEC it would drive four high-torque, oil-cooled and planetary geared electric motors driving each wheel directly at each hub.
No transmission, all-wheel drive, increased ground clearance, lighter weight and all accompanied by the howling shriek of the turbine! UBER VX! Muwhahahaha!
Oh, and it'd run on 100% Ethanol to make up for all the environment it'd be tearing up. :bgwg: