Interesting sound clip. The bike in the clip has a bit of decel pop, characteristic of the lean fuel injected emission compliant engines of today.
I see it has rather long intake runners and it looks as though the runners house the FI bodies unlike the faux carb bodies on the other vertical twins (Bonnie/Scrambler, etc).
Finally, it has a Gates Kevlar belt designed right here in Michigan north of Detroit at Gates' research and development center.
I'm not a fan of a cog drive belt. It's cheaper to produce than a drive shaft and without the inherent torque rise of a shaft or the maintenance of a chain, but I've never warmed to a belt drive. They all remind me of a Whizzer.
I think my Bonnie sounds better....and I have no decel pop.