B&W 800d's or MAGICO V3's?

This may not be the popular opinion, but I have B&W Signature 800's. At this level there are minor differences and many sideways moves.

Spend a few evenings listening to music that you love on your 800d's and ask yourself if you are really missing anything. Most likely not.

You have a great system, keep the 800d's. I would suspect the V-3 would be at a disadvantage in the lower octaves.

They are both dynamic designs at roughly the same price/quality level. No question the 800d's are better for HT than the V-3 and are as good (only different) for audio. There are lots of sideway moves at your system level. You better love the next pair of speakers before you move to them.

Why are you considering this specific change?

Magico speakers are really something special. They don't sound like conventional box speakers, more like dipole ESL or planars, with the dynamics of a good box speaker. They take advantge of both worlds. Very good design.
I wish I could afford one pair . For now I enjoy electrostatics with tube amplification and this combo is also magical with vinyl. Have a listen to ML Summits or Magnepan 20, Magic....ohhhh !!!!