thanks for the plug jeff
yep... i should be able to make it work for the R's exhaust. you'll have to sacrifice about 2" of length FYI. but sound should be nice and flow should also be improved.
to answer the unasked question, NO i can't do anything about the expansion chamber in the header, sorry. doing some interesting work with a local R owner (actually, he's doing all the work, i'm just blabbing some ideas), and although possible, it's proving to be enough of a project that it's not exactly an easily offerable/marketable item. for the curious folks, sorry... it's his project so i'll let him post pics/announce results when it's done. he's a board member so i'm sure he'll share when he's ready.