The newer pro line tires have tried to address this problem by adding more ribs to the inside of the tire, What volracer has suggested will work, Part of the problem is the stock pro-line foam breaks down in one or two runs, Ofna makes a molded foam insert that works really good. Why are you running max mulcher tires? Here in the states AstroTurf is plastic, If that's what your running on wouldn't a smaller pin work better? well anyways GRP also makes an exultant tire for the Hellfire (they do have the right off set) it has a molded foam insert also. One other thing I would try is going a bit heaver on the center diff, 20,000 or 30,000. If you put a 14 on it should take some of the abruptness out of the H fire as well.
I didn't say it was your fault, I said I was blaming you.