In my experience the full fairing is a major advantage that pays off nearly as much as some extra cc’s. I’ve ridden my Ascot 500cc single air cooler from Toronto to Detroit near non-stop and the things that made it less than comfortable; the upright riding position and the vibration. Maximum comfortable sustained speed is <120kph (75mph) and if I tuck in as much as the standard bars will allow and shift my feet to the passenger pegs I can pass at 145k (90mph) Wind turbulence blows you all over the place, particularly behind transport trucks.
Fuel economy suffers at anything over 70mph, which is not so much a problem with cost as the reduced range and a lot more vibration relates to chain drive than one would think, chain drive is definitely more efficient for power transfer, but after you ride a shaft drive bike the reduced vibration benefits become very apparent.
I like eon’s BMW suggestion:) too bad they still don’t offer smaller displacement boxer twins, that is a great design for giant riders that see gravel roads on occasion. It was the K100RS aerodynamics that sold me on my Beemer some 25 years ago, sitting upright it is comfortable and actually vibrates less at 145k+ speeds, wind resistance does not increase appreciably as you approach the rev limited 235k mark, but the damn cars and trucks look like they are backing up at you 
