Khorns will rock your son, I owned a pair of 93’s for many years, and still have a set of 00 LaScalas, but I recommend a tube setup over solid state, they seem to sound alot warmer with tubes in my opinion. They do need corners, or he can build a false wall designed for Khorns with diagrams on the net(not expensive). I would also recommend he join the Klipsch website and the forums section there has a wealth of information he can utilize, enjoy!