I recently installed an RPI exhaust on my 545, and the shop guys welded the RPI. So I've got a brand new EasySeal exhaust clamp that I didn't even take out of the packaging. It's manufacturer part number 733-5978. Here is a retail site for the same part. Please take a look at that site to research fitment; my answers to any such questions would be uninformed.

$20 shipped to the 48 contiguous states.