I would say one of the nice things about SB Acoustics Drivers is that many of them offer very good performance to cost. Of course, their Be Tweeter seems to be setting the standard… others that were as good or better either disappeared (Tranducer Labs) or are just silly expensive for minimal performance gain.
Regardless, the finished version of that Illuminoso was selling for over $7K, and for the price of the kit you got everything but the cabinet.
I’ve wondered since Rick passed if he had a partner or family member that would keep the business together. He was very well respected in the business. I got to meet him in 2019 and heard his Cali-4 design at the CAS. Solid work.
Regardless, Jim Salk is leaning pretty heavily on many SB Acoustics Drivers with that 9.5" Woofer holding down the bottom end of his SS9.5 Flagship Speaker with the SB BE Tweet up top. It's his Mid Range choices that are really very interesting with options from Accuton, Eton and Audio Technology. He still uses Seas in many of his designs along with Raals.
ScanSpeak is no doubt near the top of the food chain, but the cost of their drivers is pretty high. I would love to play with their Revelator and Elipticor gear...but oh my the cost!
As for premium XO components, I wouldn't bother. So much of that stuff falls into the same category of high end Cables: nonsense. If there were measurable differences in performance, it would be a different story, but there simply is not any evidence: other than subjective opinion detailing how gold-oil is different than silver oil in a cap....
I'll stick with Audyn Q4s until someone can really show me something incontrovertible to make me want to spend on specialty products from Clarity, Mundorf or Jansen.