DYI upgrading B&W N805 to Diamond 805?

The Mills MRA are the best "bang for the buck" resistor for a crossover. The Claritycap MR series are also excellent and will far outperform the ICW polypros that B&W put in there. What's interesting is ICW makes the Claritycap line.
   The current 805 Diamonds have a 1st order crossover in them now and B&W uses Mundorf cap( not sure which model) on the tweeter.

   Here's a link to the B&W service web site where you can download a manual for any of their speakers for a list of cap and resistor values they use:

      http://bwgroupsupport.com/manuals/bw-service

I have a pair of N805 in a second system that I recently replaced the caps and resistors only in the crossovers( There are two crossover boards in each speaker, one for the mids and tweeters and one for the woofer). Huge improvement! I didn't touch the inductors. The factory crossover parts are the biggest down side of the N805, cheap ICW polypro caps and sandcast resistors. I replaced the caps with Uptone Musicaps(no longer being made, but I found a couple of sources for them) and the resistors with Mills MRA. The sound now has transformed the speakers from just okay to extremely musical and dynamic. It was a bear, though, shoe-horning the big film and foil caps in there, but I managed. 

Alex,
  I provided a link in my above post to get the manual for the N805 which shows the cap and resistor values. Here is a copy from the page:

    1) LF Crossover

R1 5R6     11W   Ceramic Wirewound    BENNIC Resistor
C1 6u8    250V  Polypropylene             ICW
L1 1.45mH         small air core


   (2) HF Crossover

R1 3R3     11W  Ceramic Wirewound    BENNIC Resistor
C1 4u7    250V Polypropylene             ICW
C2 10uF  250V Polypropylene             ICW
L1 0.15mH        small air core

When I pulled the factory caps and resistors out of my N805 speakers, they matched exactly with the values from the manual.