Hi,
the point is Bemani compressor mounted and certified -> Ok.
HKS Silent Hi-Power mounted but I will need to pass a noise level test, so i'm looking for a way to be sure that I will pass that test else I will need to reinstall my stock exhaust and re-pass the test and as you could expect it's not free, they ask 300 Swiss franc per test.
So if there is a way to reduce the noise level just for the test that's what I'm looking for !