Hmmm - I'm not exactly familure with the R32 setup.
On my S4, if you look directly into the ends of each tail-pipe outlet, you can see the valve, basically a butterfly valve, just like in a throttle body. It is open with the engine off, at idle, and at high engine revs. It is meant to close somewhere around 1,500rpm, and open again at about 5,000rpm.
In your picture, which way is the front and which way is the rear of the vehicle?
That black nylon bodied valve in your pic could be the one - try feeling above the pipe, and see if there is a metal rod with a ball joint, about 10mm diameter. If you can push this in direction towards the black nylon body, maybe ½ to 1 inch, then it is probably the one.
Mole grips wont really help - just pull the black rubber tube off, it is held on with a crimp clamp, you should be able to wiggle it off, but you might skin your knuckles! Go for a drive, but I bet you won't really notice any difference, apart from more noise (a drone, which plagued the Mk4 R32) at criuse, then SWMBO will tell you to put it back on
. Spray some WD40 and use pliers to shove it back!
Rgds
