I'll admit that one time I did hear a tremendous difference in equipment - Twin mid-priced Velodyne 10" subwoofers to Twin EP800s. No contest.
Tweeters - really no.
Similarly, with my tube amp, according to the tube 'experts', I was supposed to hear significant differences after tube rolling - nope. In fact the similarities between my tube gear & my SS receiver were surprising to me; however, the glow & heat of tubes is really wonderful to have in one's room on a cold winter evening...