I need to see a show of full breakdown of the judging mechanism before even attempting a split/second build. We know nothing that is actually required of the car and are requested to build blindly in the dark.
At this point the rules for the build are as follows - "a car that has the highest top speed is best, must have 2.5 offroad, no budget limitations since I can sell at a loss, MAY be a hatchback, but not necessarily", which is REALLY not enough to go on.
@Vri404 is correct in her statement that the challenge needs serious work.
You made this challenge to have some fun, but in my experience "fun" in automation comes only after the "hard work, tons of coffee, swearing, trying to figure out how to ballance or min-max and lots of scrapped builds later", after you see the results of all that work and those are good or entertaining.
You probably do not know that, but running a challenge requires even MORE work and is very frustrating, especially when you start going into more complex ones (the ones that don't go "one with best acceleration to 100kph wins"), and start adding random crashing and playing with formulas. Your challenge DEFO needs a lot of formulas to determine who's going to drop which building when, and who's going to avoid it and how it will affect the lap time THIS CURRENT lap. I am hoping that you got all the challenge plans laid out already, if you don't - it's a long process, so I'd postpone. If you do - we'd need to see it.