Originally Posted by Rpracing1:
Tires definitely........Seem too many guys cheat with a berm..........If you hit a tire , it is your own fault..............JMO 
Not always your fault. They guy in front of you can park on the cushion, power across the track into your RF, and slam you head first into said tractor tire. Hurts like a MF, never mind the bent frame.
Berms or guardrails.