CF is smaller diameter than aluminum so it can spin faster before it gets to the vibration (if it ever does).Why would a carbon driveshaft fix the issue? Is there any confirmation of this? Seems the first step is check pinion angle. 3 degrees with pinion and trans output parallel is supposed to be ideal. Mine is pretty low so I need to get it up in the air level with weight on the suspension to check mine (hoping to do it the next warm day).