50 sounds about right (stock). Once you guys start doing some of the mods (I would believe these are stock figures) on your bike, you'll start getting a little less than that.
I get around 130-140 MPFill-up without tapping into the reserve (I believe). And I have quite a few mods such as, Buell Race Kit, Airbox delete, open airbox, re-routed hoses, and TFI (dobeck).
I run 91 Premium Unleaded
So by the sounds of it, you guys get way more MPG than what I'm getting. Seems like you guys would be getting at least 10-15 more MPG on HWY than what I'm getting.
Possibly because I ride pretty aggressively (sometimes) being the jerk on the road.
MY 2¢