I highly doubt THAT exhaust tip is actually sitting on ANYONE'S shelf. Most retailers nowadays simply drop-ship from the manufacturer. If I were you, I'd just call Borla and see what they could do. Their site only lists catbacks for the Xfire, but they might have a tip that could work.

OTOH, there's an enthusiastic Xfire owner in old Blighty, Simon Wood, who's come up with a rather nifty design. If a couple hundred owners press him just to make the tip, I think he might oblige