"How is it out on the highway, doing 80mph or so? Wind buffeting? Windscreens? Have a 75 mile roundtrip commute to work, mostly at highway speeds. Good bike for that?"
It'll cruise at 100+. You need a windshield though + lower wind deflectors (I have Triumph's) to cut down on turbulence.
>"MPG? Range before needing fuel? 87 octane?"
89 octane is recommended. I get 33 mpg. You should get 200 miles.
"How's the stock seat?"
Sux. The pillion is worthless.
"Aftermarket?"
I have a Corbin dual touring seat with backrest.
It's a delight.