I use my NS5000 (they are superb) with a CODA #16 amp and Holo Serene preamp. The amp is rated at 150 | 300 | 600. It is great with the NS5000 and I think the most powerful amp I have tried with it.
I also have a Sanders Magtech that is 500 | 900 watts, while it is an excellent Class AB amp it does not have the same thunderous bass of the CODA #16. The Sanders is a very strong amp.
Next Friday, I am going to demo the SimAudio North Collection 761 (200 watts) with the NS5000.
I guess watts and power that I hear are not the same. Otherwise, the Sanders should have been the most powerful with the NS5000.