I haven’t. I’ve looked at some of his stuff, not this one specifically. My impression is that most of his stuff is good. I wouldn’t be surprised if his kit really does make this speaker perform well. Unfortunately, many speaker OEMs spend more on looks than sound becasue subconsciously, that’s what many people who buy consumer grade speakers make their decisions on.
So if you take a speaker box, premade that you can buy on craigslist for $60, put components in it that are better than the originals, partly because technology marches on and partly beccause you are spending more than the oem did, you can make a nice speaker. GR does the research for you to see what components sound good together. That is the theory. I haven’t tried much of his stuff but I did build speaker cables somewhat based on his design, I modified it quite a bit, and they are superb.
I think he does a good job helping the modder/bulider like myself, but his prices are not cheap. He has to make a living and it looks like his volume isn’t very high.
Jerry