I should have posted this before swapping to coils, but I've noticed a clunk sound coming from rear axle area (mostly passenger side) when braking. This only is audible to me when it is cold started. When I was installing the coils I checked all the suspension parts in the rear. Didn't seem like anything was loose. My first gut was that the endlinks were worn, but they seemed to spin fine when I had one side of it off. I know this doesn't give you all much to go off of, but curious if there are common clunking causes from the rear.

 

I know for a fact that some Sway Bar Links will only click when under load, I had an issue with the stock ones on my MDX that would only click when installed but If I removed them they would feel pretty darn smooth in the hand...
Swapped them out for MOOG units and bamm problem solved.

 

to follow up on this issue, i just upgraded my sway bars and replaced the end links with ingalls.

and to correct, it was a click rather than clunk sound initially. the click is still there after all was replaced, but does not happen as much or as loudly. the fact that it is still there leads me to believe it is from something else. it could be that i got ingalls (oe-like) vs heavier duty ones like moog or performance ones. but i doubt it.

all the nuts and bolts on the end links and sway bars were fairly loose, it didn't take much to remove them.

 

Check all the rear arms. I recently replaced a lower arm for a worn bushing. The click was barely perceptible and the only way to reproduce it with the car in the air was to wiggle the tire(like checking for worn bearing).

Also, check that the brake pad feet aren't shifting in the slides