[BB_cuda]

it takes the following for me to hear this.
On a very very smooth road.
Going about 15 to 18 mph.

I hear a synchronous (i.e. one beat per rev) light thump thump noise. I have already had all 4 tires rebalanced. If I drive any faster, I do not hear anything. I have considered wheel bearing but they normally whine higher and higher pitch as you speed up.

Background for those that hadn't read my other postings/threads.
2011, 335d, tuned and deleted, 60,000 miles
M3 front wishbone and tension link. Front E90 M3 sway bar.
Ground control M3 conversion coilovers (uses Koni sports)
Ground Control camber plates
M3 strut brace
Rear upper guide, wishbone, and lower camber links now are M3
Bimmerworld adjustable rear toe links with aurora spherical bearings.
Rear E90 M3 sway bar

I have not lowered. I'm actually about 1/4" higher than stock m-sport which is about 1/2" lower than base OEM suspension.

Powerflex Black rear subframe bushings/ purple diff bushings.
Wavetrac LSD conversion

I discovered the noise about a month ago. I plan to put compact spare onto each corner separately just to rule out each of the wheels (or perhaps get a change in noise).

One possibility I am considering is the front giubo. I don't hear anything detrimental but am concerned that continuing to drive it this way may be causing other harm.

EDIT: I left off a couple parts that have been changed (fr camber plates and M3 strut brace).

[BB_cuda]

I did some math and computed the frequency of my wheels spinning at 18 mph. I'm getting 4 Hz. That is way faster than what i hear. It's more like 1 Hz.

A coworker down the way who has an E36 tells me he had similar noise at around that same speed and it was related to the center bearing in his driveshaft. We aren't saying that its my center bearing but rather a similar rotation rate is at the driveshaft.

[BB_cuda]

Knocking back up there. Anyone like to chime in if they have dealt with something similar please?
Thanks