Hi Bruce,

Just a quick question, when I install the disc's on my 4 inch Supertrapp Supermeg. I use the large metal collar pressed against the end cap and have both pressed onto the discs, now I have seen photos on the Supertrapp website showing the same setup so thats ok but have also seen people not bothering with that large aluminum ring? eg. just the screws going directly through the closed/open endcap then discs into the muffler body. So is the large metal collar necessary?.