How do I power my 800D(3)s

Matt, I have never owned 800D3s but have owned 803Ds. For me the B&W's sounded best with lots of power behind them. The more power I gave them the better they sounded and I don't listen at loud levels. For example, I had them paired with one McIntosh MC352 and then vertically bi-amped with 2 MC352s and then with MC601 mono blocks. For me a tube amp just doesn't have enough power to really let the 800's sound the best they can. I also believe in room treatments, vibration control and better cabling. Just my 2 cents.

Congrats.  First, invest in room acoustics. GIK Acoustics has great advice and products.

Next, tubes man. These are definitely speakers I'd pair with Tubes a-la AR, CJ or if SS, Ayre.

What a great position to be in, the new B&W are a formidable speaker.

The real question is why are you posting this question? Didn't the speakers come from a dealer? Are you seeking advice because you are not sure which brand or combination of components? Or are you seeking different choices from what the dealer was recommending.

It comes down to taste, and price. There are many good combinations which will work well, a famous pairing is the Electrocompaniet Nemo amplifiers or the smaller AW 400 which are very musical and were voiced with the 800's.

The issue with the B&W is the Diamond tweeter is very ruthless at revealing flaws, you are best with a slightly warmer amplifier, choice of dac and cables is also crucial.

I work part time for Audio Doctor in NJ, the owner Dave has 27 years experience in system matching, give him a call 877 428 2873

I would look at Bryston, 20 year warranty on amps and preamps. 

B&W and Classe have a corporate connection of some sort, which is why they are so often shown together.  Classe is good, but there may be better options.

As others have noted the dealer you purchase the 800s from should help you find the appropriate amplification for the speakers and your room and offer in-home demos. I wouldn't buy a speaker in that class from a dealer that wouldn't accommodate you in every reasonable way.

Personally, I would go with a pre/amp combination with at least 200 watts for the 800s. I love power and I have never heard a speaker that didn't sound better the more high quality watts that were sent to them.

You will enjoy the buying experience and the speakers more when you deal with a good dealer. Good luck and have fun. You are getting an outstanding speaker.

Cheers,

Scott

Classe certainly makes fine amps, but as noromance notes, you should have a dealer involved with setting up your speakers and demoing a range of appropriate amps *in your room.*  The one you like the best is the best amp for you.

Given your mention of a streamer, I encourage you to seek out the best possible source material and source components.  That's another job your dealer should help with.   

Congrats on your purchases; enjoy!

@Matt-gf,
There are lots of members here on Audiogon that can give you some very good answers to your questions. The problem is most answers will come from their personal preferences and no one answer is correct or wrong. Just like if you work with three different professionals you will probably get three different answers.

Here are a few options to consider:
Do you prefer the sound of tubes or solid state?
Do you want an integrated amp or separates (amp/preamp)?
If you want separates, do you want one amp or monoblocks?

The speakers you mentioned will work with 50 to 1000 watts and are 90% efficient, so I don't think you can go wrong with any answer you come up with from above.
In addition to what I have mentioned, what type of budget are you working with?

Best regards...

Sell the speakers, give the money to charity and buy a Sonos 3. 
On a more serious note, at this level you should work with a pro.