I have moon audio silver dragon v3 on my he-6 and he-500 and with the mods they are amazing. silver cable for me was a good upgrade that complimented the mods very well. unfortunately with the mods and my silver cable, it has become even more apparent that my ef-6 is inadequate for my he-6. I need a good speaker amps.
I spent the afternoon with Drew at Moon Audio yesterday and he recommended the black dragon for my HE-6. I listen mostly to classic rock and that may have influenced his recommendation.