The only double blind tests that were ever done showed that people cannot hear anything in a double blind test........so show me the results of phase shift of an amp....or .001 versus .1 percent distortion
If people can't hear a 3 dB difference in distortion when a controlled test is performed, then either your "everything matters" mantra is wrong or your tweakies produce a greater than 3 dB increase in distortion. Seems people can only hear these claimed "improvements" if they pay you for them. More "trust me" as the money changes hands.