I upgraded the crossover replacing sand cast resistors with Path Audio and Mills MRA. I replaced economy tier Solen caps with Jupiter Flat Stacked HT Caps. I love these for their beautiful tone. They are no longer available as the manufacturer found it hard to make any money on the time consumed and difficult built process these require. I had a special stash.
I also used the newer Jantzen Alumen Z caps on the mids. They are very musical and open and the perfect choice for reasonably prices caps needed in tight spaces. Great choice and result. Much better than the Solen caps they replaced.
I used the Audyn True Copper cap on the ribbon super tweeter replacing a very cheap film cap.
Finally I replace the electrolytic shunt cap with a nice Clarity CSA.
The results are just fantastic and well worth my time and effort.