ive got a varex muffler on my s14
its a full 3in turbo back system with a pucnched out cat (previous owner) one lil resonater, then just the varex at the end
when its open sounds like normal exhaust with a cannon on the end
when its closed it sounds stock volume, ie hear the engine over the exhaust
I still wouldnt be thrashing it 100% with the butterfly closed, but it would definattly be alot better or the engine compared to those drift/apexi oes where it completly blocks the exhaust
when it used to be on my old 180, had it closed so i could quitly drive to the track, then open it up there so it would be like a normal 3in exhaust
i dont have a vid, but if you search varex on you tube theres a fair few of them
im actually thinking about getting it mounted further back in the system like a mid muffler then have it going to twin tips, to get rid of the big cannon look