Capacitor

200 percent sure its auydn Q6 cap 100uf 600 vdc

I recently upgraded my entire crossover with huge, huge improvement! https://forum.audiogon.com/discussions/millercarbon-s-mega-moab-mod-meander
The two smaller value caps I was able to do with the very highly regarded Jantzen Alumen Zcaps, with a Duelund JDM Silver .01uF bypass cap. There was one cap of 125uF which would have been very expensive to do that way. So instead I used one 100uF and one 22uF Jantzen Premium Elko, with a 3.2uF Alumen Z bypass cap. (Voltage btw is not a factor, that is for use in a tube amp or other applications not in a crossover that will never see even 100V.)   

Pictures of actual parts used are on my system page here https://systems.audiogon.com/systems/8367


Alumen Z are not cheap, but compared to Duelund they are! And they are very highly rated. http://www.humblehomemadehifi.com/Cap.html

Thank you very much, Rick!

If you go this way please be sure to pay attention to your space and the dimensions of the upgrade parts as the physical size of quality parts is huge compared to lesser quality parts!

Also everyone focuses for some reason on caps, but do not underestimate the contribution of inductors and resistors. Read my thread, I did all of that and more, and it is not just a huge improvement it is like better than I ever heard before.

Jantzen Standard Z-cap (it comes in 100mf 400v), otherwise most likely you should add up values to get the 100mf you are looking for. Depending on your space and budget, economic availiable alternatives would include Solen Fast, Audyn MKP Plus, Mundorf Mcap, Clarity cap SA. If budget is no issue then add whatever you fancy.

There's no easy answer. According to the laws of physics, the best cap is the one with a value closest to 100uF, (a twenty nine cent 101uF cap should in theory perform better than a one hundred dollar 110uF cap, both 100u nominal). However, considering the tolerances of capacitors, the designers had to settle on a nominal value of cap that sounds best to them, and reject values that fall out that tolerance. So if your expensive substitute falls out of that design tolerance, it may not improve things at all.

(I am assuming this is a commercial made speaker and not a DIY. If it's a DIY then the answer is: experiment with different makes)

What value  is important the uf or the vdc