NO RESTRICTIONS.....!!!
OPEN CLASS RACING, run what you like
Look at Chrissy P and D R.....running a 13.5t and 10.5t motor and both doing really well with a lower turn motor at seaham.....!!!
As chris has already pointed out, lower turn motor reduces the strain on your lipos and will reduce your tire wear....!!!
Choice is yours
For club racing, Im going to run a 10.5t motor in 2wd and a 7.5t motor in 4wd.....its only going to help my racing making less mistakes and be more consistent
Only problem i've got with our carpet is all the bloody fluff that gets everywhere and a pain in the arse to get off the drive shfts all the time.....and the static does help much either
lol