Hard to get any detailed info on those. I do remember that B&W likes high crossovers around 4K. You really need a goal to know which way to go.
If your crossover looks anything like this...
http://www.ebay.co.uk/itm/B-W-MATRIX-1-SPEAKERS-GOOD-WITH-LINN-NAIM-AMPLIFIERS-WORLD-WIDE-SHIPPING-/290946525755
... I'ld focus on replacing those electrolytic caps (white rectangular, mostly labelled 3.3) with same value poly's. The stuff on the bottom right is protection circuitry. Don't get carried away with expensive boutique caps on nearly antique speakers. However, if you tell someone like Chris at PartsConnexion what you want to improve, he will have suggestions. PCB soldering and unsoldering is usually not a area for novices.
If your crossover looks anything like this...
http://www.ebay.co.uk/itm/B-W-MATRIX-1-SPEAKERS-GOOD-WITH-LINN-NAIM-AMPLIFIERS-WORLD-WIDE-SHIPPING-/290946525755
... I'ld focus on replacing those electrolytic caps (white rectangular, mostly labelled 3.3) with same value poly's. The stuff on the bottom right is protection circuitry. Don't get carried away with expensive boutique caps on nearly antique speakers. However, if you tell someone like Chris at PartsConnexion what you want to improve, he will have suggestions. PCB soldering and unsoldering is usually not a area for novices.