This tweak business is all about creating an enhanced experience, right? Perhaps you're looking at the wrong end of the equation. Anybody who is so restless as to require constant variance in the sound delivery of their system will always pursue the moving carrot. Better I think to tweak the listener end than the system end.
A few years back when the Mpingo disc was the cure-all rage at the time, a guy responded to a question about its efficacy by saying he uses his every day and it never fails to make his system sound great. The trick, he said, is in how you use it. He put his on the arm of his listening chair under a tumbler containing 3 fingers of Scotch.
