Like most, I find this post troubling. While test-driving a '12 535i xDrive M Sport, I noticed a vibration. The salesperson did too - we casually chalked it up to a wheel needing to be balanced. When I took delivery of my '12 535i xDrive Sport (I preferred the car without the M body treatment), luckily it was smooth. It continues to be smooth. It came with 19" 10-spoke wheels and Goodyear all-season RFT tires.
I found it interesting though, that in Car and Driver's long term test, they replaced 2 bent wheels and had 4 additional bent wheel repairs done. They also replaced 2 damaged RFT tires. Not pretty... Otherwise though, they liked the car. See below...
http://www.caranddriver.com/reviews/...ad-test-review