I have Frazier Black box ii with what I believe are Heppner horns. I think one has seen better days. Interested in options... Can the driver's be replaced? Diaphragms replaces (I think i read they are phenolic)? Otherwise, I have wondered about replacing the horns completely but do not have knowledge about the ramifications of that as far as the basic crossover they have and all of the other considerations. Appreciate any info, thoughts, and advice.