the cf is eerily strong actually, and the fact that its extremely light lowers the "critical speed". Critical speed is the speed at which the driveline starts to bow and form a jumprope like effect. At the low weight of cf, that speed is realy really high, probably somewhere you wont even get to. If you're changing your driveshaft, make sure your differential and tranny are acting right first though... dont want to send a jolt to a lackluster mechanical part.