I've searched this forum to death and know all about the shimmy issue with the thrust arm bushings, hubcentric rings, etc. I have a slight rumble at highway speeds and I don't think it's any of these issues, and here's why:

1.) It was very bad on my old tires. I got new tires (and balancing) and the problem got better but still wasn't perfect.

2.) Feels like I'm just running on a very bumpy highway, rather than any side-to-side motion.

3.) Braking has zero effect on the rumble.

4.) It manifests around 55mph and gets a little worse all the way to about 70 mph where there is a bit of a lull. It's not really noticeable at 75 or above.

5.) I have stock wheels, so no hubcentric rings.

6.) There is no noise when going over bumps or when normally driving.

This leads me to believe that my wheels were not properly balanced by NTB. I've read about static vs. road force balancing but I'm not convinced. I've heard conflicting reports about the effect of both, as well as how sensitive the suspension in the e34 is. So I'm asking everyone, what have your experiences been with wheel balancing? I'm sure nearly all of you have had your wheel balanced at some point, so where did you get it done? What method did they use? What were the results?

For me, I got my wheel balanced at NTB when I bought Potenzo G009 tires to replace my Turanzas with 45k miles on them. The rumble greatly improved but it is still present. I've thought about taking my car to the BMW dealership, which has one of those fancy Hunter GS9700 machine to get it balanced again but I don't want to waste money if there's a cheaper, better solution.