i leave it on 1.0 enertia for Cars
But when you like it increase enertia do it
it works for every car, addon or stock....
and take a look on this
if you set x="2.000000" it feels like controller damping for left and
if you set y="2.000000" it feels like the car is longer
if you set z="2.500000" it feels the car get more high
(when the car spin out, feels more realistic)