I've got a 2009 RG with 107 ci, T-Man 590 cam, Lozano Bros. heads, SE ac, 10.6:1 comp., and an EMS tuning control unit. I get 35 - 38 in town and on a trip I just took to Colorado riding two up with both bags and a king tour pak full I got 44 - 49 mpg. The top was on two lanes to and from the Grand Canyon. Running 75 mph with the cruise on I got 45 mpg. I'm really happy with the mileage on this set-up. It is about the same as what it got stock. The EMS has made a difference.
Mine gets around 40 regardless of tune, temperature or wind. I usually accelerate pretty hard, and don't do less than 75 or so on the freeway so I don't expect it to do any better.
I don't baby it when I ride, and at least half of my riding involves stop light to stop light (which sucks). Usually I get 35 combined with 2 up.
Going on a ride to OC, MD. next week. Should get a good idea of hwy mpg.