The center support bearing was eliminated on the 350z but the G35 still had it, as do plenty of other cars in the Nissan line up not to mention 100s of other cars and makes. Driveshafts need to be balanced as assemblies and the ends need to be in phase. People often take driveshafts apart and then fail to align and match things up correctly. They basically put their own driveshaft out of balance and they blame the bearing.