E87 M Sport Rear Suspension Knock

[shadowface]

I'm looking for someone to point me in the right direction. In the last few days I've replaced a snapped rear lower control arm on my E87 with M Sport suspension and a day after that I've swapped worn out rear OEM shocks for Bilstein B4S (a downgrade, yes, but since I have no money to buy B8 yet, I will have to live with this).

Since then I've been hearing a knocking noise coming definitely from the rear left side of the suspension, but I'm not sure what it might be. The rain here (damn Manchester) doesn't allow me to get under the car, so I thought maybe someone with more knowledge about BMW suspensions can shed some light on that.

From what I could find so far, people are either mentioning the stabiliser link rattle (I had to undo it to get to the control arm), top mounting of the shock absorber (bump stop mainly), or one of the bushings (but I suspect these should squeak rather than knock, or am I wrong on this?).

Just to say, I've transferred all the old hardware to the new shocks and used new bolts and self-locking nuts to mount the control arm as well as the shocks. Anything I may have done wrong? Or maybe after 120k miles on the clock I should replaces the top and bottom shock mounts, the bump stop and other auxiliary stuff with new elements?

[shadowface]

Never mind, thankfully, the weather was alright, so I could check the car.

I found what it was: one of the wheels was a bit loose and it was knocking upon rapid forward/reverse. Tightened it to appropriate torque and it's now perfect. No noise, all the bolts are tight, so nothing else is running around.

Handy tip: once you put your car down off the jack, make sure the wheels are tightened properly.