For really tough decibel limits you will need these extra add-on tailpipe silencers! An easy slip-on/swap-over at trackside they are built using 0.8mm thick polished Stainless steel TIG-welded for best quality. 350mm long with extended tailpipes to better spread the noise energy over the tarmac. Don't be fooled by a simple plug-in deflector! They don't work at the 'Quieter' tracks. An absorption silencer must be at least 250mm long to be effective. I did use that length initially but given the stricter tracks like Brands/Goodwood/Thruxton it was found the 350mm versions were a better solution. Circuits like Bedford you swivel the tips left and right, split the decibels between the trackside mics! For Brands, point both tips infield, away from the mic on the outside of Clearways.
If you want to run at 90-92dbs, you need the 2bular QP system plus these add-ons. With them removed you have a decent-sounding exhaust approx 95-96dbs.
If you are happy running at 'noisier' tracks Silverstone/Donington you can run the 2bular Track/Road system with these add-ons. With them removed you have a really good exhaust note!