I had this made to allow me to pass the IVA test. took a honda type-r engine down to 97db.
its in stainless steel but has discoloured with heat. a quick polish and it will be fine. 2.5" bore. it is full of baffles and wadding.
Just fits in the boot. obviously it might not fit everyones but its a good start.
£80 pick up in person, Wetherby Leeds or York.