I think most of us fall under the "sensible tweaks" category--placement, calibration, room acoustics, etc., like you said, Dr. House. I guess the more exotic things I've tried is tube rolling, felt surrounds around the tweeter, and socks (yes, and even straws) in the speaker ports to control bass.

***********
"Nothin' up my sleeve. . ." --Bullwinkle J. Moose