"mainly" whatever has been done that caused the manufacturer to choose to market the suckers with a new name. Moving a horizontal tail up or down on an aerobatic design has far more significant effect on the rudder coupling response of an airplane than adding horsepower has to the flight envelope in general. For us to know the most changed things between different versions of any aircraft would take a lifetime of study.

But it's real easy to assume that when the model number matches the engine size there is a link.

The 300 had a reduced wingspan and larger ailerons than the 260 and had a 300hp engine.

Since Flugzeugbau came out with the 330 and it too has: wider-chord rudder, a larger elevator, and a powerplant producing 330 hp, And all their models seem to be named after the engine size, then that mfg appears to do just that for the numbers he chooses to plug into his model name. But there are also 330L, 300SHP, 300LPs and such.

So if you want to identify one of the Flugzeugbau Edges, just saying "Edge" isn't enough. And just saying 300 won't be either. That is, if you want to tell someone which airplane you're talking about. Because they all look pretty similar to most people.

Does all that matter? When it does, it does. When it doesn't, just call 'em what you want. But if the aerodynamic differences are what you're trying to identify, it'll probably take the whole name, letters and all, to do that.