At the first organised Talk Morgan trip to the Gaydon Motor Museum, the one where we had a preview of the new workshops. On the Fosse Way en route to the meeting, I kept on looking for "the super car" with the throaty exhaust.
It was only when I got to the museum that I realised that the wonderful sound was coming from one of the groups Plus 4's.
I spoke with the guy briefly however, I cannot remember where he said he got the exhaust. Hopefully if he is on here, he will let you know. The sound was great and not offensive at all.