So I took the bike for afew rides, none far enough to require a fill up.
The most noticable change is the amount of noise coming from the intake. When I really get on it I think the intake is louder than the exhaust. Almost a popping noise, probably because it's taking 1/2 liter breaths.
There may be a slight increase in responsiveness, but I also gained a tool box.
I'll report back on mileage later. Was averaging 63 pretty consistently before.