Ben,
Thanks for posting this up again. I think I mentioned that I have the howl too as mentioned by 13dog previously. Mine is consistently heard at 80 mph (give or take +/- 3 mph). It more like a humm, but it only is apparent at that speed and goes away if I'm over or under that speed. Question, is it really an issue worth getting the rear changed? Is it damaging the car?

Did your repair fix the problem?

Thanks,
SS