PeeweeCSHL

Howdy all!

I'm hoping there is a suspension guru out there that can point me in the right direction.

I've got a 2008 550i m-sport w/ 65k miles. At any speed it has a certain unsteadiness to it - like a mount that holds something that moves is loose. Bumps feel a little sharper on one corner (I think front driver's) and I can feel a weight inconsistently shift back and forth unsteadily even on a mostly flat road. I feel it most through the pedals, foot rest, and seat - a little through the steering wheel but not since I replaced the bushings. I don't hear anything from this unsteadiness, only feel it. I've never had a passenger notice it, only myself I feel like an automotive hypochondriac sometimes!

Another, possibly related symptom, is I get a creaking from the driver's side wheel well on heavy cornering. I have a steep driveway I need to cross at an angle to not bottom out and I hear that creak every day. The creak starts as that corner takes on weight. Then the creak happens as that corner deloads and I straighten out. This creak is still present with the new bushings.

I've had all of the wheels balance multiple times by several shops. Even road force balanced. Found one wheel had a bent rim that has since been fixed - which brought to light an out-of-round tire that has worn back to roughly round (vibrations at 66mph have consistently smoothed out over the last 1000 miles from ok to good but not great).

I've replaced the thrust arm bushings (not whole arm - so original ball joint) and the wishbone/control arms. I replaced them because the bushings were visibly torn. The new ones stiffened it up but the unsteadiness is still there. I don't see any other bad rubber on suspension.

I also replaced the driveshaft guibo - thinking it might be on it's way out. It looked good as did the center driveshaft support. Even though it looked good I decided to replace it while I was in that far anyway.

This unsteadiness is present on 99% of the driving time, very rarely (more commonly after the car has been up on a lift) the problem isn't present.

When I jack up the car and try shaking each wheel at 9&3 or 12&6 nothing moves.

With the windows rolled down, I can hear the "woosh" sound of my strut and/or shock compressing. Is that normal?

One last clue is the symptoms are more present right after spirited driving - even if it's just in a straight line with no heavy cornering. Heavy breaking doesn't seem to cause it to be more or less prevalent.

My current thought is one of the following:
- Strut Mount (My best guess - How to inspect without complete disassembly?)
- Thrust arm ball joints
- Sway Bar Linkage
- Strut/shock blown?
- Motor Mount?
- Tie Rods (Steering is tight and car tracks fine on highway - so this is doubtful)

What tests should I try out or what should I inspect? Thoughts? I'm open to suggestions!

Any help is much appreciated! Thanks fellow 5 series-ers!