I will touch on that.
60 fps isn't going to greatly increase range and isn't going to allow the use of a significantly heavier be. For example at 400 with a good hop up you'll likely run .30 maybe a .32. At 300 you will run .25 maybe even a .28. The effective range of a .25 vs a .32 isn't all that different even at a lower energy. Now we are talking even less ~60 fps isn't gonna make much impact at all and with a well tuned hop up you can likely run the .32 in the 340 fps gun just as effectively as a 400 fps gun. Main difference will be flight time to target and it won't be by much. Without busting out the calculator I'd say maybe at max range (250-300ft or so) it'll be around 0.25-0.50 secconds
that's not that much really, my 500fps bolt action has about a 2 second flight time out to 450ft when running .40g bb's
search up the bbbastard msed and check out some of the links. The site seems broken up a bit now but Google will link u to all the info.
you can see the physics behind airsoft and how different velocities and bb weights effect range