[petek]

My typical overthink analysis of this question:
Ignoring other aspects of the game, if you want to go just for the absolute minimum lap time, I suspect that an automotive-style drive train and ackerman steering system would be the ticket. In either rear-wheel drive or four-wheel drive form, in principle there should be less frictional losses and smoother direction change control.

One gotcha with this is your un-steered wheels need to compensate for the different driven path length around corners. A differential can lead to sitting still with one driven wheel spinning while drifting (sliding) a solid axle takes more finesse to drive and re-introduces frictional losses, so I'd opt for differential control of the motors driving the wheels (sync'ing them to the steering angle).

In the real world of Overdrive I think all this is moot, because it will be pretty darn hard to get a clear lap to make use of the little bit of extra speed you might have. Besides, us oldtimers recall a certain Evil Machine with six-wheel drive and tank steering that just plain flew around the field a few years back, proving that drive system can be fast, manuverable and push like an irresitable force - without any complicated steering system.