A driver is a driver is a driver. I would assume that the crossover network between the mid/tweeter and the woofer/tweeter (same driver, remember) is the same. Therefore, the twin 5.25" drivers of the M22 handle mid and bass. Just fine. Although you probably want to add a sub to the M22s. Although driver dimensions don't add, you do get more bass from 2 5.25" drivers than from one.

I am the Doctor, and THIS... is my SPOON!