Grip: Grip is simply an acceleration multiplier for the motors, more grip = faster wheels, stronger drive impulse. 1 grip on 4WD = 2 grip on 2WD, all motors being the same.
Negative grip seems to work just fine, it doesn't even invert drive controls. More research on negative grip should be good, although for now it makes no difference to me.
Resistance: Resistance is merely how slippery the wheels are. 1 resistance is OK, at 5 resistance you start to drive worse. 10 resistance is very slippery. starts creating havoks while driving, while 20 resistance is unplayable. 0 resistance is good driving, although it is a lot of drifting. Very low positive values of resistance seem to be best, although I must test more.
Negative resistance: Unplayable because of instant havok teleport.
Negative hitpoints: Weird things, maybe it replaces fracture with HP or something weird. More research needed.
