Depends on the vehicule and kind of suspension you have. In a vehicule the only rigging you shoudl have to do is anything that you want to move in an animation. So if you dont have doors opening and closing. And you dont have the trunk or hood opening or closing. Dont touch them.

for offroad suspension, pistons, stuff liek that seems like the biggest thing....

I wish i could help... just dont do things that wont be noticed. Kinda like dont rig a whole body just to move a finger...