I currently have a set of KLF-10s driven by a Sony STR-DE845 that I absolutely love. They're supplemented by a 20'ish year old Infinty BU-150 sub. The sound, to me, is just stunning. However, I feel driven to experience a pair of La Scalas (AL-4) just because I have read so many positive things about them. If I swap them out, what will I miss/gain/lose? Is it true that I absolutely must drive these with a tube type amp? If so, can these types of amps be purchased reasonably? Anyone want to convince me not to make the switch?