Well the guy said you shouldn't upgrade to a carbon gear shaft because it doesn't spin....um..well the stock metal one doesn't either.
Now if both don't spin then the carbon one would still be worthwhile if you're looking to save weight because it's 10X lighter...yes I've weighed it.
Now if you want to use the heavier metal gear shafts to prevent traction rolling then you might want to recheck your suspension setup/tire setup because it's definitely out of whack.
You want weight low in the chassis not high up like where the gear shafts re located...lol. To get better handling you want better weight distribution not a heavier car otherwise you'd get better handling with a dump truck right cannon?