I experienced very similar issues once with my E46. Turned out to be blown RTABs, and that solved it. In your case, assuming the RTAB replacements were good quality and installed properly and the alignment was done properly, the next thing I would check are your tires. How old are they, and how's the tread? Have you had your rims balanced recently to check for bends/warping?
Worst case, bring it to a good independent shop (one of the sponsors on this forum) and have them take a look at it. I'd recommend Stance Factory as they're suspension specialists and should definitely help.
'12 M3 6MT Alpine White + Fox Red Extended | '09 328i 6MT Space Gray + Black