You will have to tell us what you think of the wind at highway speeds compared to the Busa. I have been toying with the idea of doing the same thing you just did, but have not looked into it too much.
I wear earplugs, a balaclava, and a Quiet Rider to enclose the bottom of my helmet in this cool weather.
My helmet also doesn't buffet or blow around.
I'm sitting upright very comfortably, and with more leg room than ever possible on a busa.
Handlebars personally are in a great place for me, arms relaxed outstretched at roughly a 45 degree angle down from the shoulders. There are several other aftermarket bar bends available to help make the bike fit even better.
A 60 or 70mph wind in the chest just seems to hold me there, but definately no feeling of blowing off at around 100mph or less(or much greater I'm sure). Just sitting, cruising, with good suspension and handling.
I was sitting about half way between B-King and stock busa with the Spiegler topclamp and bars I had on my gen2 Busa.
All of the bar setups I had just moved me up little by little allowing the busa windsheild to blast me with air in what felt like a smaller space.
I've sat upright several times at gps'd 150mph(on busa), that's around the point when force of the wind becomes very strong. I'm sure I could sit upright faster, but have grown too old, and wise, to try
I'm sure that with enough road, the right gearing and the right conditions, crouched on the gas tank, that a derestricted B-King could easily see 190mph!
Ramble over.
The seat shape fits me great, it holds me in place, yet allows me to move around easily.
The overall seat height is also higher, as well as wider than the Busa.
I can flatfoot Busa seated with slightly bent knee. B-King has my legs straight and both heels off the ground.
I like the B-King's ergonomics in general.
My guess is that the U.S. market didn't like the big mufflers and that's why the B-King never really took off here. As it was and still is sold currently in other parts of the world(or at least was up to this year)
As said, it's so underated. The B-King simply is a Hayabusa in a more upright riding position.
I think alot of the Busa riders that complain the Busa is too small, do taller seats and buell peg/peg lowering mods, would love a B-King if they rode it.
If you're interested, go find one to ride. At least see if it's for you.
Your cruise control mod would be a really tight fit too, but you could get it in there.
I've been considering getting the B-King for a few years now. This deal just happened to come up after I finally decided that I was definately going to sell my Busa buy a B-king.
Best bike I've ridden in years, loved it as soon as I rode it.
No going back to a Busa for me.
Not when I can have the Busa motor in a big dirtbike frame.