The compound seems rigid but not hard if that makes any sense.
They are definitely much harder than the sportsman pro softies, but they really feel like a good quality compound.
No, I have not done any burnouts in it as I have been babying my clutch due to some unresolved issues, but I have gassed it a coupe times and heard some tires sqeeling which I never heard before with the sportsman pro's.
I have a line-loc that i need to install, then I am going to thrash the crap out of my transmission before I yank it out and go through it.
If it really pisses me off I am going to put an automatic in it and be done with it.