I had a e36 for 2 years nothing but a headache and it only had 78k when i sold it. I replaced all suspension parts. The rear shock bushings were so bad i caught it in time before they did some damage to the towers.
I know i replaced all bushings, rear control arm bushings because when i was flushing out the tranny i inspected the rear and the bushings were toast. Also when ever i had my window down hear an annoying squeak that went away.
Thats weird… Ive always had good luck with the e36. Theyre the type of car it seems where if the right things are taken care of on them then they will run forever.
also check RSM if you hear a loud clunk. Describe when you have this vibration and where it is coming from. How old is your guibo, even if it looks find it most likely isn’t, and if that has been bad for a bit you need a new CSB
EDIT: Too bad you didn’t post this earlier, I am getting my RTAB tool shipped back to me from Roc
EDITx2: Describe the sound you hear better, that description sounds like RSMs
is the vibration at certain speeds or conditions? when you brake does the car pull to one side?, does the car pull while driving down the road and letting go of the wheel?