Hi,
I also only went for the Scorpion to fit symmetrical MM panniers. Seemed quite quiet which suited me well. The received wisdom seems to be, for performance improvement, the headers need upgraded. If I didn't have the MM, I doubt if I would bother changing the can. However, motorcycles are very personal things, and if you fancy a different can just go with what makes you happy. Oh, just remembered; Scorpion may give a very long warranty - worth checking.