Roger on the sounds - years ago I was working in the yard with my kids and a helicopter was approaching, "sounds like a Chinook" I told them to which they replied, "what's a 'Chinook' dad?" "It's a big helicopter with two horizontal rotors." Sure enough, an Army Guard Chinook swung overhead and the crew chief waved to us. Kids thought that was pretty neat that I could recognize a helicopter by the sound.

Now it's fun to hear a Harley coming and tell folks it's a Sportie, open piped - maybe Vance and Hines.. After all, Harley did patent the sound of their V-twin so that the Japanese bikes couldn't copy it!

As mentioned - the V-Dub is unique in it's horizontally opposed (boxer) configuration and thus produces a unique sound.