What to add or change for my system?

This is my first post, so please have pity on me if I break any rules.... :)

I immersed myself in this hobby a few years ago, and I'm completely hooked.  And best of all, my wife is.....almost hooked.  I initially purchased speakers from Axiom, OPPO 103D from OPPO, and Parasound preamp and amp from a local dealer.  These were connected with Kimber Timbre cables.  I also have a Furman Elite power conditioner.

All of that changed in December.  My system now consists of:

• Martin Logan Summit X speakers; purcahsed new on AG
• Plinius Hautonga integrated amp; purcahsed on AG
• Oppo 105 that has been modded by Tweak Audio for even better audio; purchased on AG
• Bryston BDP-1; purcahsed on AG
• Gustard X20 DAC that has been modded by Tweak Audio; purcahsed on AG
• Gustard U12 USB interface; purchsed new on Amazon
• Clear Day silver speaker cables; direct from Paul, a wonderful person!
• Avanti Audio interconnects; direct from Avanti
• Furman Elite power conditioner; Audioadvisor

As luck would have it, I just got a nice bonus and feel the itch to add to, or make better my system.  Not knowing what to consider, I'm hopeful to get some suggestions from you.  If this was your system, and you had $3-4 thousand to spend, what you add or replace?

Thanks for your thoughts!!!