Anyone ever found a bad driveshaft in the ls? I had a mechanic friend of mine put my car on his hoist and the deflection on the driveshaft is terrible. Of coarse the dealer argued with me last fall that it was all cause of the tires. Makes me wonder, when it's that obvious to the naked eye, how they could have ever missed it. Definetly were my vibration is coming from. Anybody else ever run into this problem?