Preamp to go with Pass Labs Rushmore Speaker

I'm asking for my friend in China. He has a pair of Pass Labs Rushmore speakers, and he doesn't like the Pass Labs preamp (don't know the model) that he currently has. Can you recommend a couple of high-end preamps (other than those from passlabs) that best (or better) match these speakers?
You should mate the pre with the power amp and not the speaker.
The speaker is active (has built-in amps)so in this case matching the amp is matching the speaker. What is the input impedance of the speaker/amp? Are the amps essentially XAs?
I also own a pair of Rushmore speakers by Pass Labs. I am using a tube preamp with my Rushmore's . Calypso, by Aesthetix .
Try the Allnic L-3000. I tried one and loved but $10K is a little more than I wan to spend on a pre-amp.

Too little info for a good response....

What is it that he "doesn't like" about the Pass pre?

What model is it?

How much is he willing to spend?

Is he willing to buy used?

Pass Labs XP-10 or XP-20 Preamps
Kind of hard to be specific without knowing if he wants a more relaxed sound or a sharper one. Short of that, I'd recommend looking into some of Conrad Johnson's newer tube preamps. I am very happy with them driving my Pass amps.
I have found the Audio Research Reference range (Ref 3 or 5) of preamps to work very well and is a safe bet with the Rushmore's, which I have been using for a number of years now. The SMC Vre-1 may be better but ultra sensitive to cabling and source components. Surprisingly I have found the older XO Pass pre a bit too bland for the Rushmore.
I too would recommend the Pass preamps, but the OP has given little info. To change the topic slightly, I'm interested to read that there are a few Rushmores out there. I hadn't realized that Pass sold many of these. Could I ask the owners what speakers they compared these to and what they sound like. I have all Pass electronics and have not read or heard anything about the Pass speakers. Thanks.