x4 on forgiving barriers. i havent broken a TC in a couple years, went to one track, that had the smoothest track ever, had some rigid unforgiving outer barriers. first time on the track within 5 laps both my TC and 12th came off practically shattered. i've only broken my 12th scale once and that was when my rear wheel got caught on something and ripped the rear pod.
I'm torn on going back to that track because it's the smoothest track i've ever been to, but the outer barriers make me not want to go back. Only track i've been to with that much carnage within 10 minutes.