How do I power my 800D(3)s

Just stop Bo.

Matt asked about amplification not your speech on trufi and speaker preferences.

I think a Pass labs X-series will be the best option. It depends how much money he wants to spend. The cheapest option for a new one is the X350.8. When he has more budget I would go for a X600.8 set. 

Even with his 800D3 it will outperform the Classe amps. This is based on the fact that the level of diversity of the Pass is a lot bigger.

You can play very loud with the 800D3 with both sets. Even at low volumes you will have a powerful controlled low freq.

The mid frequencies of the Pass are more open and diverse compared to the Classe. It can make more a 3 dimensional shape of an instrument or voice. With Classe I never auditioned this level.

The Pass is also able to let you hear the difference of each sound of an instrument. When you listen to competitors it is more like a sound. It is more difficult to hear all the layers in sound of voices and instruments.

Most people have no idea what the differences are in cables when you use them with  the same speakers, amps and source. First you need to know the properties of the loudspeakers, amps and sources before you can make a choice which cable is the best option.

An Audioquest, MIT, Transparent, Nordost or Taralabs will have different properties. When you compare them they build the stage differently, the sound is different, voices and instruments will have a different size and even the blacklevel is a lot different.

The most test I did in over 18 years of time were done with cables. When you have no idea how an instrument sounds in real or how big it is in proportion, tell me how you want to choose the right cable?

When you listen to the endresult; connecting a speaker, amp, source and cables togheter. You need to understand what the properties are of the cable you use, or you will not understand why the stage and sound is what you hear.

This is why trial and error is audiogambling. It is important that you use the right properties to create the right sound and image. And that voices and instruments have a realistic proportion

Any of the higher end amps should do it justice. I am running vintage 703 with classe cp 800 and their digital amp ca d-200. I've never heard my speakers sound so good upgrading from rotel.

Symphonic Line Rg4 monoblocks.... Whatever  amps mentioned here  are just mediocre at best and don't not even come close to these....  if you value musicality, the truth of timbre, etc...

For the  tube designs the Mastersound PF 100 limited monoblocks, or Jadis 120 s with EL 34 s only! the Jadis PA 150 is great too, but make sure to get it with EL 34s (Golden Lions KT 77s are alrite)... However with the Jadis you might deal with reliability issues, thou the new circuit is much more reliable, the company has somewhat spotty service in USA, but if you want to duplicate your last autumn opera gala premiere experience at the MET, these three would be my top choices.....