B&W 803 D3 speakers - which amp?

I think I will talk with my local dealer

Unless they’re blood, they’ll just sell you what they want, there’s no way they will say sorry can’t help out in this case if they don’t have the correct amp.

Just educated yourself in reading the above impedance/phase graphs I posted, which I think may have gone over your head, as you didn’t comment on them.
And then you’ll be able to make an informed decision without any bias coming into it. Google is your learning friend, so are Stereophile’s comments in their bench test pages on impedance v -phase graphs of speakers they test, take a little time to learn it and you’ll not only get the right amp, but your ears will thank you as well.

And don’t listen to anyone’s recommendation on amps, unless their first question before answering is "what speakers is it going to drive" and they know the impedance/-phase angle of them.

Cheers George

B&W 803 D3 speakers - which amp?

An "impedance" vs "-phase angle" graph has never been done on the 803’s, but:
Here are the impedance phase graphs of all of the 800 range, no reason to believe the 803 won’t be the same, which are all very hard to drive in the bass (70hz - 900hz) given their measured impedance and also when it’s combined with -phase angle (EPDR) which can look even lower to the amp that hust the impedance alone.

These speakers need amps that have good current delivery, an owner should seek out amps the "can come close" to doubling the 8ohm wattage spec for each halving of the impedance, if they want to get the very best from the bass as well.
EG:
8ohms= 100w
4ohms= 200w
2ohms= 400w

802 https://www.stereophile.com/images/616BW802fig1.jpg

800 https://www.stereophile.com/images/511B800fig1.jpg

804 http://www.prespeaker.com/images/201702/B&W-804-imp-thumb-650xauto-15553.png

801 https://www.stereophile.com/images/archivesart/801fig1.jpg