@improvedsound Wow, that outboard cabinet is really impressive! The attention to detail off the charts.
I see you put aluminum cooling fins on the bigger resistors. Tom had me try a similar cooling mechanism in my build. But it seemed to produce an echoey anomaly. Subtle on many tracks but I heard the best sound without the aluminum heat sinks. One of the advantages of an outboard XO is you can just vent the cabinet, no need for heat sinks. Simply add holes to the bottom and, maybe, top of the rear panel. When I was considering outboard, I imagined the top of the cabinet would just be stainless steel mesh.
I see coils on left side of coax and woofer have the same orientation, almost stacked. I suspect those are close enough to cause interference. Here are a couple of resources for your consideration:
http://www.troelsgravesen.dk/coils.htm
https://techtalk.parts-express.com/forum/tech-talk-forum/1439851-inductor-placement
Finally, the binding posts look like Thiel gold over brass (or equivalent). There are better choices out there, and it appears you have the budget. I used Cardas rhodium over silver.
Please hear those as friendly suggestions, not criticisms. You have done a lot of hard work!