> In double blind trials or audiophile I can hear the gold plating sort of way?

I think this type of comparison with espresso is comparing the differences of far different orders of magnitude. i.e. Impact of a bad grinder, poor bean distribution, or tamping force is orders of magnitude larger than the difference cable connectors makes. The difference in the end result is also (and I'm committing audiophile heresy according to some) far more apparent with espresso.

As someone who brews espresso at home, and is a bit of an audiophile (mostly in the home recording domain), this is spot on. If your grind is too coarse for an espresso, it's very very obvious.

No, it's very obvious. There is some audiophile tendencies at the very expensive end of the espresso home setups, but there's a pretty noticeable difference between a good shot and the same shot ground ever so slightly finer. Because espresso is so strong, any off flavors are very strong and noticeable.

Maybe an analogy here is gold plated wires don't make any difference in a home setup (well, they make zero difference in a digital setup), but when you're AC/DC blowing the roof off an arena with your speakers turned up to 11 bad equipment can be pretty noticeable.

I've avoided the espresso gear habit because I don't think I drink/want to waste enough coffee to have a good shot every time. But several years ago I went to a class where the instructor poured a bunch of slightly different shots of the same coffee ground finer/coarser, extracted longer/shorter, and dosed with more/less grounds/water. The variation in the flavors was surprising. But when she described pouring several shots a day to get the beans dialed in as they use different batches of beans. I decided it didn't make sense at a home scale for me. In a cafe setting is one thing, but in a house of 1.5 coffee drinkers not so much.

A friend doesn't mind, but he roasts his own beans as well. I've had great espresso from him, and I like it but I'm content with little filter