Power Amp for BAT VK-31SE

I am currently using the 31Se in balanced mode with a Bryston 3B-st power. The logical choice for a partner would be a VK-250 or VK-600 (should I decide to spend that much). I was wondering if anyone has had success with a non-BAT power with a BAT pre. Looking to spend $2500-$4000 used.
I used to own the BAT VK-30SE. It worked well with all of the power amps I tired with it. Pass Labs X-250, old Kinergetics KBA-75, Counterpoint SA-220, Graaf 5050 tube amp, etc. Not sure how the 31SE compares to the 30SE but overall I perferred other preamps to the 30SE for dynamics.

Happy Listening.
The 31SE is a pretty good step up over the 30SE. Just like the 51SE is much better than the 50SE. Dynamics do improve, you have great preamp with the 31SE.

Why would you want to try other amps? BAT SS and tube amps are wonderful. I've owned VK200, vk60, vk75SE and now VK150SE's...The amp/preamp combos from BAT are hard to beat. I'd get a VK250 and not look back. Maybe buy a 2nd and run them in mono down the road...For just over 4k, you could get 2 VK60's run them in mono if you want high powered tubes....
Although I don't own a BAT preamp, I am using a tube linestage, ARC LS-25 with Pass Labs X250.5 amplifier with my B&W N803 speakers. This amp used is within your budget. Great amplifier. Drives the B&Ws easily and sounds dynamic, detailed and musical. You can run it with balanced cables with your BAT and I think it will make a nice combo.