I can't actually see what using a more expensive driver would bring to the table with Meridian speakers??

The reason we sometimes pay extra for a Morel driver over say the same size Vifa is to make it easier to build the cabinet with the sound we want.
Say you want a cabinet that is no more the 15" in height and no deeper than 10" you could only do that with XXXXX driver if you wanted to reach 45hz and keep it flat, or, you could EQ out the peaks and dips but that would actually cost you more.

Now, with Merdian building DSP speakers you can just EQ out those peaks and dips, which is what they do with the DSP33 over the M33, Obviously they try and get it as close to right to start off with, but having DSP'ing in their speakers makes driver choice a lot easier.

No Darling, I've had it months!