First tube preamp recommendations (under $5k)

Right now have di20he -> terminator -> he9 -> pass x350.8 -> ATC scm7 / NS5000.
I am thinking of introducing some tubes into my chain. I like the sound I am getting but want to explore what tubes can do to the sound (slight warmth, biggest soundstage, better layering etc etc). Don’t want to go to nuts on price. If price is over $5k would consider if its really exceptional (but for sure not over $10k). Totally fine with used. Balanced would be nice but not mandatory.
So far I am thinking RP7, EVO400, bhk. Any thoughts?
If you listen to records, the CAT Preamps have an excellent phono stage as well as line stage. The only drawback is that the volume control is stepped, but the quality of it is unbelievable. They are built to last.
Audible Illusions.  L3A (which is what I own) or the newer L3B.  These are line stage only, that use only 2 6H23 tubes. Or, if you want phono stage included, M3A, or the newer M3B (4 6H23 tubes).
ive owned my L3A now for about 5 years, and have not had one issue.  The sound is wonderful, but be advised this is a single ended preamp (RCA only inputs and outputs) there are no balanced inputs or outputs.  
You’re new to tubes. I respectfully suggest you avoid vintage gear, no matter what upgrades or "restoration" have been done. I’m a veteran in the world of vintage tube gear and have FINALLY had enough. Over the years, I’ve upgraded and done a lot of periodic maintenance. It’s very costly. The final proverbial straw: One of my mono amps blew up a few days ago. Done.

One other thing, the Wells Commander is a hybrid, not pure tube preamp. It does sound very good, but it is a boutique item, so the resale value will certainly be impacted downward.

Full disclosure, I'm now considering many options, including Black Ice, which could be a heck of a lot for the money.

Good luck.