I suggest taking an in-depth look at the wheeled vehicle PhysX driving model. Many vehicles don't handle as they should in my opinion, in regards to responsiveness, speed and weight. As these are to some degree subjective findings, please do verify the below details:
Lizard SPAAG - too fast and nimble
AZU - too slow and cumbersome, problems with scaling hills
GOLIATH - oversteers, surprisingly nimble
JARA - oversteers, hard to control at all
A serious issue with many wheeled vehicles is a bug causing the vehicle to randomly change direction slightly to the right or the left, making the driving a chore.
Affected vehicles so far:
I will keep expanding the list as possible.