new crossover upgrade for Nautilus 801?

No, but Kimber Kable has created a circuit called the Kimber Diaural circuit that is said to make all conventional crossovers obsolete. Read about it in the current issue of the Absolute Sound. It was a big rave at the CES and has also been discussed in Stereophile.

Mikenificent1, Are you referring to the Northcreek systems crossover for the older matrix 801's???

Yes I already know of the DiAural circuit. I contacted B&W and they said they think it is not compatible w/the N801. I'm still waiting for a reply from Kimber. Thanks for the reply though.