Have no idea about the technical name but there is a hinged flap inside the right tailpipe of the dual exhaust system (looking at it from the rear of the car) that is actuated by a vacuum driven rotating wire arm. The little black plastic actuator was knocked off leaving the "flap" inside the tailpipe to rattle and arbitrarily rotate noisely around.

I have not found a new "actuator" and would prefer to just remove the flap and let both exhaust tailpipe operate unconstricted. Will it hurt anything mechanically if I just plug the little vacuum hose and yank out the flap?

Hello rbw welcome to Audi forum,

I read this in a site "When the flap in one of the tailpipe is closed, the exhaust is rerouted through the rear muffler and exits through the other tailpipe. The flap opens when accelerating at higher loads and engine speeds. The exhaust now takes the direct route to the outside, producing a fuller, more intense sound". So i don't think there would be a much of a difference in the performance except for the change in the exhaust sound. Hope this helps

Regards
R.B.N.J