My only point was, that if the angles are a bit off and will stand up to that sort of abuse, the angles being a few degrees off in a street car it should live forever. As for the driveline harmonics, never have had them come in to play. The countering angles on the two ends of the shaft will match in a perfect situation, however I've built many street cars that are a degree or two from perfect and never had a problem with harmonics or anything else. Oh yeah, and going through the traps at 150+ mph will bring in any harmonic or other imbalances that are present in the car...