I've got a strange one here. Since I got a new front tire fitted and having to go into the boot to get my locking wheel nut. I noticed a couple of days later a weird metal knock coming from the rear right of the boot (where the exhaust is).
Now, I've checked the exhaust and both the brackets are firmly in place. My car has the JCW Sound Kit exhaust and it's very solid. Have pressed down on the rear right and left of the car - no knocking (shocks are very solid). Have wiggled the exhaust and it's solid. Have checked under the car and the bushes seem fine.
I've also removed the rear parcel shelf, lowered the rear seats, made sure the tool kit is seated properly and removed it also - it's definitely an exterior metallic knock
When driving around town and hitting pot holes/dips and dives in the road I can only hear the knock with the window down! And it seems to be from the rear right or directly under the center of the car - possibly the cat? Though I can hit very hard pothholes doing 40MPH and theres noknock, but I can hit the same ones at 20 MPH and hear a knock! :/. Baffled! :S
A mate of mine is a mechanic and has seen a fair amount of R50/R53's come in with worn rear anti roll bar links and bushes and he's told me it's definitely not that - as I would hear a very noticeable knock from the inside from the boot.
He's advised it's most likely an exhaust knock as it's an exterior sound. Has anyone come across a worn mount/rubber on their exhaust/cat? Or even a knock coming from the heat shield? Just need a direction on where to look...