The Ring Chris?
Don't panic, see below. Hope to add my name to the list tomorrow, any DB Killers for Numpty Termis?!
The marshalls do conduct testing, both targeted and random. However, based on various experiences, we have concluded that Nürburgring GmbH is keen to be seen to be doing something to satisfy the concerns of local residents[1] without actually keeping too many people off the track. [1] Is it just me, or does it seem bizarre to live inside a race-track and then complain about the noise?
For example, they sometimes pick out perfectly standard (and quiet) vehicles to test. Phil Gardner's theory is that by picking lots of vehicles they know will pass, this enables them to be seen to be carrying out lots of tests and report back that 95% of them pass, thus giving the impression that noise is not a problem at the Ring. They have also allowed vehicles to continue after failing the test by a margin, with one person suggesting that there is an 'unofficial limit' of about 100dB.
However, the bottom-line remains that there is an official 95dB limit, and some people have been sent away for being too noisy. So if you go there with a noisy can, you run the risk that you might not get to play. Also, the German police have powers to confiscate noisy cans, which can spoil your day, especially if you've ridden there ... So unless you are going by van or trailer, and have the stock can with you for a swap if needed, I'd think about whether the extra 3bhp or whatever is worth it, especially as the Ring is not a power circuit.
If you decide to risk it, most people who get singled out for testing do so by being silly. Don't rev your engine in the car-park, keep the revs as low as possible when passing through the barriers and don't go haring off from the cones at full whack. If you wait until reaching the bridge before opening it up, you have a much better chance of getting away with it.
If you see them wandering round the car-park with a noise-meter, that is an excellent time to wander off for a coffee: if you and your keys are not with the vehicle, they can't pick you out for a random car-park test.
http://nurburgring.org.uk/noise.html