I wanted an EVC exhaust that offered the best of both worlds, very quiet when I want it to and the least restriction when on the loud setting. The one that offered the quietest sound was the JUN BL EVC from all the videos and reviews I have seen, but didn't offer the best performance and sound when on the open setting. Main reason for that is that it still retained a muffler on the open setting and the main pipe dia is 60.5mm then branches to 54mm for both pipes including the valve which is 54mm, so ultimately in the open mode you are running a 54mm exhaust, any back pressure will have to flow through the restrictive muffler for the quiet mode. I checked with several suppliers but non were willing to assist in checking with JUN if a change was possible. Finally got in touch with JUN BL directly and convinced them to do it, the big muffler for the quiet mode is still retained, however for the open mode the canister is deleted and the pipe in open mode is a full 60.5mm including the valve. Can't wait to get it installed, waiting on the NGT primaries to arrive.