IMO if you are gonna play LOUD you need to change the sqawker. To get the most out of your khorns I would go w ALK crossovers and his wood trachorn. The khorn is PIERCING at loud volume. I ran mine w/ 2 Mcintosh MC2102's in Mono w/ outstanding results. I now run 2 MC2000's in Mono w/ even better results. I've compared smaller tube amps as well and they were lacking in bass and dynamics. You can't beat larger tube amps w/ Khorns. don't know were you live but you can come have a listen.
Tube Monoblocks for heavy music on Khorns
What tube monoblocks would drive Khorns the best for big bass/heavy metal music? I obviously can't go the SET route for the BEST sound. I was thinking about some BIG monoblocks to help the Khorns 15" driver REALLY move. My room is small. I could even experiment with adding a large sub like a Velodyne HGS18 in the future, too. However, price is an issue. Another interesting Idea, what horn speakers can really compete with Khorn for around the same money for reproduction of bass, Etc??