I run onna indoor bluegroove clay track. I run a sc truck with a tekin rs and a 9.5 I can defiantly tell a little difference in the same brand pack 35c compared to the 65c. That being said I can take the timing advance in my esc and turn it from 85 to 90 with the 35c and it will feel like the 65c. So in conclusion I just run 35c cuz they are fine for me, the only thing the higher c does is hurt my checkbook!