It's been a while since this thread was active, but I thought I'd attach a link to an interesting blog by Peter Aczel (aka The Audio Critic). He discusses some new software (Audio DiffMaker, sort of like the Unix Diff command, but for audio components), which could potentially make subjective listening tests easier to perform and detect differences b/w components.
http://theaudiocritic.com/blog/index...Id=35&blogId=1