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?
smodtactical
So my wife actually bought the ref5 that my dealer has on consignment ($6900 CAD all in). Tomorrow I will talk to the dealer to finalize pickup. She was tired of my waffling and just made the decision. But I am concerned that its not a very good price for the ref5 and that the ref 5se is a pretty big step up from what I read (and can be had used for not much more). So should I cancel and wait for a better deal?