Replacing the rotors on my Infiniti G20 solved a nagging vibration problem that I thought was a tire balance problem.
I started a thread a week or so ago titled "bad tires or bad balance".
Got some great input and links to check out.
I recommend getting your tires balanced at a shop that uses the Hunter GSP 9700 balance machine.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".