A 1.4 inch exit (four inch Beryllium voice coil) compression driver firing through a large waveguide going down to 300HZ will simply be amazing. The bass dynamics and drum sets will explode and pin you to the back wall. The clarity will astound you. The lower the frequency you go with a compression driver then the faster the whole speaker sounds.....and more coherent.....assuming great waveguide design. Of course, you need state of the art crossover parts, damping, wiring and jacks......hopefully, we get it all here for around $10K.
The M3/M4 can be upgraded for better sound. Clayton may do this later. I suggested this to him: Make a super external xover using the worlds best parts/wiring and hardwire the wires to the xover parts so that the only connector is the push on connector to the driver. This way you can just remove the stock wires from the drivers and hook up the external xover and in 10 minutes have a way superior speaker. You could go back to the stock xover/wiring anytime to see what the improvements are in time as the new xover burns in. The xover parts and wiring are good in the stock speakers but nothing like what can be had for more money. He is simply limited by the selling price. The resistor on the tweeter and the coils and caps and wiring are all in the signal path.......replacing them with higher resolution parts will take the speaker to new levels of resolution and clarity and dynamics. The stock wiring is inside the speaker frame.....this is not great nor is the fact that the stock xover is vibrating with the speaker. By having a separate xover box that is damped off the floor and its wiring going straight to the drivers is optimal for best sound. Another thing I suggested was to add constrained layer damping material to the back of the large stamped frame woofers. He could precut pieces so that all you would have to do would be to peel off the backing and apply. Cleaner bass, warmer sound, more natural sound and clearer upper midrange would result.
Of course, one could do this oneself. You would need to remove the stock xover and measure all the xover parts and then make your own separate xover copying the design using better parts and wiring. You could just start with the parts for the compression driver and bi-wire at first to ease into this. Xover parts selection is an art. All parts sound different and some expensive super parts will not necessarily be best for these drivers. But, this could be a fun experiment for those inclined (perhaps no one......not very many tweaks out there). Hopefully Clayton will do as I suggested and offer a super xover that he has tuned to sound perfecto with his speakers. I would imagine the price of such xovers would have to be close to the original selling price......so basically doubling the speakers cost.....but still way under the $10K of these new babies.......and you could buy in cheap and then get the upgrade later when you had the money. Will there be a turbo EXTREME? I hope so.