I use the Gortz Alpha Core foil inductors on the networks now, to me they are a relatively inexpensive upgrade.
We too have been using the Sonicap Platinums as bypass caps on the high pass (tweeter) cap, if you can get them (might be sold out of the .022's), a .022 or .047 uF should work fine
Have also tried the Jupiter Copper foils of the same value in the same position but prefer the Platinums there.
Have been using .1uF Jupiter Coppers on the mjdrange leg. the gen II's do work well here as well.
Another very inexpensive cap I've tried on the midrange cap is the ishay Roderstein
. I actually really like these, don't let the cheap price fool you. they do have short leads , usually have to add length to reach around a "large" cap. I keep meaning to try them as bypass's on the high pass cap as well, just haven't done it.
You can get the Sonicaps, Jupiters and gortz inductors through Danny