Uh, I think you've got that backwards: the Mistral, being almost completely a phonic x-over, doesn't share muffler volumes so at high rpm/exhaust output, it's more choked than the Stucchi, which is a true x-over in the sense that both headers are joined & then split out again to the mufflers.
Anecdotally, the Mistral fills in the hole better in the roll-on from low rpm [& will also allow fitment of the aftermarket ctr.-stand], while the Stucchi posts higher power peaks on the dyno charts & also functions better than the stock x-over down low [but no hope for a ctr.-stand w/ the Stucchi.]
BTW, for the original poster: you sure about that year on your Billybob? AFAICR, all V11 production ended 2004: 2005+ models were leftovers since the factory was in limbo during the Piaggio takeover of Aprillia in that time frame...
Thanks for all your answers, so far the Stucchi looks like the best option for sound but not sure if I want the bottom end to remain weak (if you can call it weak!)
JRT
In contact with dynojet here in the UK, will weigh up the cost of the PC3 once I have felt the difference the mods make with the standard ECU setup
Tom
Your spot on there, as far as I know the TPS hasn't been adjusted, throttle bodies sync'd or the valve clearances so I will get this done prior to modifying the exhaust/anything else.
Skeeve
Bike was registered here in 2006, so it will have been produced in 2004 by the sounds of it - how can I tell?
Thanks again