Crossover and Wiring Upgrade

@audioman58 +1 So, lets say you're only changing out parts while keeping stock values. You're not creating some Frankenstein monster here, and you could add parts in small increments so as to only have one variable at a time, don't let the naysayers deter.  You should also understand exactly what you're trying to improve, going in there willy nilly and changing out parts not good. Generally, these boutique parts are going to improve resolution/transparency, may also affect tonal balance, timbre. You also need to be aware crossover changes may expose some new flaw elsewhere in system, synergy may prove to be problematic. Now, all this assuming you have experience with soldering, modifications. If not, practice with kits is a good idea.

No positive approach , you can make only worse, Upgrade  you speakers  same brand to high end line

Check out the GR RESEARCH website.  They specialize in this and are extraordinarily knowledgeable.  They also have lots of YouTubes on the subject.

I have built one of their big speaker kits with their top flight crossover component selections and most of the people in our audio club feel these speakers compete effectively with some of the most expensive speakers in the club.

Before going to the expense of swapping out expensive parts in a over. 

Consider which Wire Type can be used between Over and Driver. 

Wire Types I am an advocate of, are D. U. C. C

and PC Triple C. 

These can be a Sole used Wire or a mix for different Drivers. 

D. U. C. C will add a hint of a fullness to a base note, or enriched a Upper Frequency with a little weight to notes or vocal.

PC Triple C is removing smearing many many Wire Types add, it makes OCC sound muddled and veiled. 

If these Wire Types do what is suggested and are liked, why not extend their usage to being Speaker Cables connected to high quality copper connectors and also attached to high quality copper connectors on both Speaker and Amp. 

This will bring substantial and discernible improvement improvement.

The Xover can be left untouched while the new experience is being savoured.

If the Cover does come back under the radar, the prep' to get the best is already done 

OP,

What model SF speakers are you thinking about tinkering with?  
I know that SF use parts that some say are below what they should be using, but changing an iron core for an air core probably won’t make much of a noticeable difference. And on another vein,  mine have an 8 year warranty on them that I’d hate to muck with.  As others have mentioned, the resale value probably won’t go up a penny even though you added a thousand dollars worth of new parts.