Upgrading crossover?

Has anyone done an upgrade to factory speaker crossover with better quality components and got good results?
I had opportunity to look at the crossover while upgrading friend’s PMC FB1 to + version, and I noticed that components were not of a high quality, inductors with ferrite core, electrolytic caps, resistors of 5%.
What are your thoughts of replacing these elements with better quality ones of the same value, inductors with air core (for example Alpha core Ribbon inductors), Solen caps, etc?