I thought I should start a new thread about this because it was going a bit off topic in another thread. So I got the new Mountune cat-back exhaust fitted to my ST a few weeks ago and sometimes notice a knocking sound coming from the back of the car when the road surface has bumps or dips.
This must be the exhaust because I never heard this before it was fitted. I had it fitted at Stoneacre in York and took it back to them so they could check it, and they say it's all ok and just adjusted the heat shield a bit in case it was knocking on that.
From talking to others it looked like a good idea to upgrade the exhaust mounts, which is also something they recommended at Stoneacre. But Mountune disagree, and in emails they have said the exhaust is designed to be used with the stock rubber mounts, and if there is any knocking the exhaust is not fitted properly.
Has anyone else has this kind of problem, even with a different car or exhaust? I'd appreciate any advice