I’m always in search of low cost tweaks. Crossover upgrades are a great candidate because there’s always an upgrade path, regardless of the price you paid for your speakers. I have Hawthorne Audio OB8 speakers. Danny designed the crossover. I hope he doesn’t mind that I played mad scientist with his design. Here’s what I did:
STOCK CROSSOVER:
Here’s a pic of the original crossover. Note that the parts are already higher quality than most speaker crossovers.

LEVEL 1:
Back in 2016, I hired a local audio tech company to install 12 ga. Jantzen copper foils on the mids and 14 or 16 ga. on the highs, and then added a Jupiter bypass cap on the mids a few weeks later. The inductors provided a significant improvement in sound, i.e., more body, primarily.

LEVEL 2:
February 2019: I changed out an Erse 2.2uF cap with an enormous Miflex cap, and bypassed the other two caps in the tweeter circuit with Miflex 0.1uF caps. I also added a Speakon connector to connect the speaker cables. With only a few hours of break-in, my system was on a different level. More detail, more dynamic, livelier... just better all around.
Here'a pic of the orginal Erse cap and the Miflex it replaced....

Here's a pic of in installed:

LEVEL 3:
July 2019: I swapped out the Sonicap Gen I's with Jantzen Superior Z-Caps. I have a single 10uF, 12uF and 15uF cap in each crossover. I chose the Jantzen Z-caps primarily for cost and quality.
The improvement was more significant than I expected. It wasn't subtle at all. More like a component upgrade. Just clearer and more musical all around. Vocals are more natural. Slight increase in detail. Deep bass is the same, but more subtlety in the mid bass. Generally more enjoyable to listen to, for sure. The imaging improved significantly.
Those caps will probably continue to break in, so the sound can only get better. Was it worth the $300 I spent on upgrading the caps and resistors? Absolutely!
Below is a before/after shot comparing the original crossover to the current one:

It ain’t pretty, but it’s hidden behind the speaker where no one will see it.
LEVEL 4?:
There’s no other reasonable upgrade path for crossover parts. For aesthetic purposes, I’m considering wooden boxes for external crossovers. This would require re-building the crossovers, and I can upgrade all of the wire at that time.
BOTTOM LINE: If you’re interested in tweaking, crossover upgrades are a great option if you have the space in the cabinet for larger caps. The cost-to-sound ratio is very good. Dust off your soldering iron and get to work! But first, if you want to keep your speakers long term, consider getting them evaluated by Danny for potential improvements in crossover design before you get started.