I am a bit confused
Do you want to modify your speakers I would speak to someone like Tony C
What do you feel is missing
They are nice speakers I am not sure you need to mess around with the crossover

Nice to see you around again, Martin!

I've been playing with the idea of upgrading my own Be-20 crossover components. The first thing to do is get hold of the circuit diagram. Then choose sympathetic components - not necessarily the most expensive. For instance, I prefer Auricaps over Claritycaps for their smoothness. Finally, rebuild as much as possible on the original circuit board, leaving the chokes alone as they are usually fine.

If you don't feel up to making a good job of it (and your speakers demand it), then have a company quote you for it. Over here, I would recommend Coherent Systems to do the work.

Yes I want to upgrade the crossovers.

The reason I want to do this is because I think I can get more out of them; I'd also consider taking a bit of the bottom end out of them (probably via DSP) and get a couple of subs, so they can concentrate on mids and highs.

I don't need to mess with anything (it all sounds good as far as I'm concerned) but why let common sense stand in the way of fun

I built these for my NS-1000Ms:

Beautiful work, how did it sound compared to the stock ones?

This can bring really good improvements to an otherwise ordinary set of speakers, though just think about how your speaker sounds now, what you like about it and where you are looking for improvements.

No point in putting in expensive components if your system in not capable of demonstrating the benefits of such an upgrade.

Always remember to keep a balance in the system, having ultra clean Teflon cables and thick film resistors or further up the latter! may not be the way to go, rather look at a quality oil filled paper or film cap with ceramic high wattage low tolerance resistors, shorter pathways, improved cabling, also consider vibration damping, inductor types, also take into account that high quality products are usually larger so if you are tight for space or cannot obtain the correct size of Capacitor then you make have to parallel or series them which will take up more space. Marks crossovers are now external which can bring benefits and drawbacks, just think why you bought the speakers in the first palace because you liked x, y and Z

Don't change for changes shake, if you are going to make fundamental changes, maybe a change of speaker may prove more rewarding. Imho