As I said before with the class regulations against high level pipes and the space available we are very squeezed for space for silencers.
Some may have read about the CRMC meeting at Mallory earlier in the month, we all know about the ACU Noise test and it is a hoop I thought we could jump, but it seems the new owners at Mallory have made a new agreement with the local council (Part of the attitude "I bought this house and now I find there is a race circuit at the bottom of the garden
". This agreement has lead to trackside meters and races red flagged if the limits were breached, which is exactly what happened. A competitor I know said "the races were a shambles I wont go again" (remember he may have paid £200 for a ride and passed the ACU test).
Now we are due there at Mallory in June, later at a 'normal' ACU race elsewhere, and one venue with no exhaust restrictions, so apart from re jetting for each venue, this our answer (talk about back to the future) a Supertrap! end unit, when it stops raining we can try and write a Db against discs chart.