Parts express sells the DATS which i happen to have one of and it measures a speakers thiele small parameters which would help you find a driver with similar properties. You could measure the one in the other speaker to help find a match. Also if you contact ian he may be able to provide the thiele small parameters, he did for me when i asked him in a PM.
DOG is GOD spelled backwards.
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M80 V3 MY GLOSS Cherry