Recommendations for replacing B&W 804s / HTM3s

for 15k on the used market, you have a lot of really good options.
Revel and Sonus Faber just to name a couple! 
BTW I have owned the Nautilus 804's 803's and 802's and if you have space the 802's are by leaps and bounds the sweet spot in the Nautilus line. 
Lee

N & S are historically important lines. Nothing B&W has topped them since, unless you go to Vivid. 

I thought of doing the same thing. Listened to a lot of speakers, and even contemplated auditioning some at home from vendors who have a 60 day, no questions asked return policy. In the end, I bought a JL e110 sub and couldn't be happier. I have not heard a speaker I like better than my old N804s ... equal perhaps, but not better. The N804 bass was a bit light for me, so that's why I got the sub. 

I feel I would have regretted selling my N804s, and you may feel the same way. Think long and hard about this decision ... current pricing for new B&Ws is through the roof, so expect to buy used if you want to stay within the B&W line.

Good luck.

hello win200, im looking to buy a used in good condition B&W HTM3s center speaker . Are you selling them ? and for how much if you are Thanks ill be waiting for your reponse

What are you using for rear channels?