both - re ride quality.
few points:
mine, at 11,500 miles is still fine
yours, I'm guessing, started off fine, but is not fine anymore?
Adding these 2 bits together would indicate (to me at least) that this is not therefore a design fault, but something that has worn out / come loose / leaked or whatever.
Take em down to your respective dlrs and let em have a look - hopefully you'll be driving in comfort again soon
