So err...let me see if I understand. You are 'jumping' off a 9' roof, and also slamming into a 2" concrete barrier to do front flips?
I would suggest investing in a lot of cheap replacements, because I don't know of much out there that can withstand that kind of punishment for long. Other than that, I would suggest custom building something to dampen the impact if you insist on punishing the poor car