Ferrofluid

@timlub Also forgot to tell u I also have and am using 2 Krell B&W BAFs. ( Bass alignment filters for my 800 Matrix.u can also see my system and all the components and cables etc etc from my profile. 

So, I hear you, but again. I would not rebuild those crossovers. A few parts replacements yes, but you would need to measure every inductor for its resistance then figure into the crossover, when the resistance changes on this tweeter, mid etc, how many other parts have to change value to keep the crossover at the same frequency.  When you change coils,  It appears to the other parts in the crossover that you have actually changed the impedance of the driver itself.  So, your speaker goes a little out of whack when you change the parts, a little more on the mid parts and even more on the woofer.  It can change a speaker to being withing 2 % matched parts to being off 20% in matched parts.  I'm being a bit tough with that description, but the point is, the more inductors there are in a design, then the more you change, the more you risk of destroying the original design. 

So, unless you just don't like the original design, I would only do key parts changes. I have not looked at a schematic, I don't know the slopes chosen or the topology of the crossover, butterworth, likwitz etc.  Now parts choice is a can of worms that very few would agree upon in this forum.  Capacitors,   There are more types than this, but in speakers, normally, you have Electrolytic, then step up to mylar/polyester, then poly carb then polypropylene, then polystyrene and lastly teflon. If I recall correctly, B&W used a lot of Solen parts.  I find the Solen parts to be very decent sounding,  they don't get harsh, they may be a little dry, but they don't do anything particularly wrong.  These boutique caps can get very expensive and yes, I can hear a difference between these parts, but for most people, I believe that they would find a nice improvement changing parts, but not night and day. So for my taste, I would take start with the series caps and all resistors.  This should make a nice change, not cost you a second mortgage and no matter who bought your speakers, the main character of your speakers remains intact and you have simply made a true upgrade by anyone's opinion.  The wrong mod can hurt their value.... I hope this makes since,  Tim

Just take it to the local mechanic 

@timlub   Hey Tim. I definitely hear what you are saying and totally makes 💯 sense. I really would like to get the most performance out of those speakers and I know totally agree what u are saying about only replacing the necessary parts and caps. Maybe some better wiring too ? I would really love for you to do the work on these crossovers for me if u would like to take on the job. I appreciate your time  everything you said to explain all of this for me. And I’m sure I’m making the right decision now not buying those crossovers from eBay. And he also sent me a pic of the new crossovers and they look totally different with a lot less parts and caps. And it looks like they are mounted on a piece of plywood and not a circuit board. If they are. I forget when I installed them when I got my speakers. 

My only FF experience was when I rebuilt my Boston a400’s. It took me maybe 10 min per tweeter . One had tarry looking FF, the other looked fine - go figure.

I replaced both anyhow. I used a meter ( $20 off Amazon ) to check capacitance of the caps and a few were off so I replaced all with film caps.

You should get meter and check them before replacing . I have a 40 year old set of ads 1230’s and and 42 year set of GNP Valkeryies and both had all caps in spec so why replace them? I’ll read posts of ADS owners sending their crossovers to Richard So to be recapped but why bother if they are fine?

Btw, a good track to show off how good your speakers are is the song by the cars called “Drive”. If they are revealing, after the second stanza , you’ll hear bongos playing a counter melody in the back ground of the “duh duhs”.