Who cares what "sounds good"? That depends on the listener and any psychological baggage (prejudice, confirmation bias, etc.) that person may carry along and the room of course and the recording too.
Audio gear quality means a single thing - to what extent does the system alter the sound without all that psychological baggage, room effects, etc? Lack of coloration is all that matters. The best way to check that is measuring it. If you don't like accurate sound, suit yourself, you are not getting good audio.
Spinorama with Kippel is as good as you will get.
I think listening to the Klippel running it's routine could sound good—as a fan of Autechre—but I reckon the repeated sweeps could be a bit maddening, so maybe some more work on the composition is called for. But you could pick up some great samples to work with.
I certainly use published specification and measurements (including third party, obviously) to select equipment and in-situ measurements for system setup (including the room as part of the system, also obviously).
But if the rule of thumb cited here—that speaker measurements get you 70-80% of the way to knowing how they will sound, and assuming the remaining fraction is more than simply the room/placement characteristics—then I expect to listen to a speaker also to know if its less obvious characteristics are going to do it for me.
Now I don't expect you to necessarily care what sounds good to me—or vice versa—but I do, axiomatically.