The weakest link could either be the $40K amps or the rest of the system at $4K. Do you think it's a good balance? How did you end up with these amps?
I think your amps have a lot of unfulfilled potential with the rest of the system. They have a lot more to give but they can't...
Before the cables maybe you should really consider listening to speakers and cd players. Digital has come a long away since the rega(it's still a good player but...).
my thoughts.