Left exhaust tip vibration (movement) at idle

[AlexT]

I have noticed that at idle, after the car is warm, the left exhaust tip vibrates up and down quite a LOT compared to the right one. Everything is tight. Is this a bad symptom of something else that is wrong? Can it be fixed by stabilising it somehow?

[shangani]

If you have a 111s (S2) or a 135R with the standard exhaust, at idle, only the left exhaust pipe is open. There is an air valve that opens the right at about 4000 rpm iirc. After that I am sure the both vibrate.

Leave it alone unless it is rattling against the rear grill, I would have thought.