RE: Realistic goal...20 fps better with new bow?
You could easily get over300 (probably over320)with the new high country bows, but you'd have to use their arrows and keep it light.
Heck, by my best guess, you'd easily top 300 at 27.5", 60# with the speed pro arrows and an 85grain head.
With conventional gear, you'll be hard pressed to scare the 300 mark, being handicapped by such a short draw.