I used some time on the testserver to try different Vehicles and, not surprisingly, came to the conclusion that something is seriously messed up there.

I drove around the track of Desert Race Track, counted a finished round without mistakes.
Initial Acceleration was done before strating timetaking.
All tests happened with 55 Vehicle use.

Maybe times might differ a little based on better or worse driving, but on the whole I think times are accurate:

NEXT Quad V.1 1 min 23 sec
NEXT ER Chaincraft V.1 1 min 30 sec
NEXT ER Wheeler Speedbike V.1 1 min 29 sec
NEXT ER Hovertech V.1 1 min 19 sec
NEXT HH Wheeler V.2 1 min 40 sec
NEXT ER Assault Bike V.2 1 min 25 sec
NEXT ER Combat Chaincraft V.1.2 2 min 05 sec
NEXT HH4x4 Chaincraft V.1 1 min 38 sec
NEXT Reveler-Chaincraft V.2.5 1 min 37 sec

Other observations:
1) Other than the Hovertech, each Vehicle has a worse turning behaviour than the Quad - which is "free" and cannot be destroyed (the turning of the Quad is awesome)
2) The NEXT HH Wheeler V.2 has a very large hitbox and hangs very fast if you come even a bit close to a stack of tires

Conclusion: Since the Quad, no Vehicle is worth it. Not even the Hovertech really, true you are a little faster, come up a little more hills, but thats all, you still risk the thing when you drive around. And the Quad has one of the lowest requirements of all the vehicles.

I can think of lots of fixes, but the most obvious is the following: Crash down the Quad. Make it an nearly crawling, slow accelerating and hard turning thing. Its a prototype after all. Better up all other vehicles a bit. And THEN maybe issue a "NEXT Quad V.2", having different colour, higher requirements and better driving - and cost.
Make it so that:
1) Everyone who chooses to risk a vehicle has an advantage of it
2) Make vehicles of the same "type" (for example 1 person transporter without combat option is a type" have a ranking. The better it is, the more it costs and the higher the requirement is.
3) And Maybe: Make Vehicles a not Free for all target - e.g. giving away the faction of the owner and having SL consequences.