Nice to see, you are all thinking a lot about the MAG12...
I think I'v seen some speakers from eminence and of course from VOLT, that had heat sink in the front of the speakers. In the case of the LABhorn it means that the heat can be dissipated in the horn (free air) and not only in the closed box (back chamber). I think this could be a good improovement regarding cooling. If the speaker itself will have less distortion with the added stabilizing ring than the LAB12 while maintaining all the TS parameters and Mechanical dimensions like diameter, hole ring diameter, overall height, self Volume, etc and getting even cooler, this vould be great!!!
Regarding noise/distortion caused by the air vent's air flow and the very close aluminium cover, it vould be nice to mage the vent opening more rounded maybe. But increasing the distance of the cover plate by 1-2 mm will help also.

Thanks,

Tako Tamas