Driver size choosing question

In a 3-way design, if the crossover point for midrange was selected around 200-2,500 Hz, what is the different between using 4 and 6 inches driver? As the frequency response of both drivers can be covered totally in that range. Thanks in advance
 
Distortion in a 4" will be higher on the lower side of the spectrum. And xmax, and so volume wil be more limited. But it all depends on the drivers used, the application and the power needed. For high-power pa purpose i would use a 12" or 15" in that spectrum, for a small low power hifi speaker a 4" or even smaller (2 or 3") can do the job. In general, the more db you want, the bigger the speaker must be. But bigger means less directive and more problems with break up modes that get lower.
 
In a 3-way design, if the crossover point for midrange was selected around 200-2,500 Hz
Any reason for that choice? Those points don't go well together, you'll be either power constrained or suffering from mismatched dispersion. If you use a 6.5" mid lower to 2KHz the upper crossover point, if you use a 5.25" mid increase to 400Hz the lower crossover point.

Ralf