Which Pre/power combo?

I am currently using a ML37/ML360S,Revel F52,Kimber 3035,KS1130 xlr and a Primare a30.1 amp.

Now is time to move to a pre/power with preferably over 500w,the question is which s/s pair would be best?

On the short list are either the ML320S/380S/326S with eitherML336/432

Or the pass labs X1 with X250.5/X350.5

I will be buying pre owned in the UK since the new prices are very high for the above units,so demoing will be hard.

I would prefer a sound baised on the warm side!

Any opinions or other alternatives wecome,thanks.
Levinson gear is way overpriced and over rated.You're paying for the panache of the name.$ for $ you will be farther ahead with Pass equipment.You may want to consider a tube pre amp with a Pass amp.Gotta have tubes somewhere in your system or it just isn't music.
I auditioned many of these components.

I liked the Pass amps.. I did not like the X-1 from a user friendly perspective. The volume jumps were huge! It did sound quite good however.

Ultimately I chose a ML 336 amp and love it. I am using it with Aerial 10T's and an ARC LS-26 pre-amp. To my ears the ARC pre was a significant step up over the X-1.

The ARC has just the right amount of warmth for me - but the speed and dynamics of SS pre's. I really, really like it and think you should seriously consider it if those attributes sound appealing to you.

I've heard some ML pre's but never long enough to make a true comparison to the ARC or the X-1.

Hope that helps a little!
The Pass XA series is spectacular, more musical than the X series. No tubes to mess with! My system couples this with the Joule Electra 150 tube preamp for an excellant system "match". The remote handles balance and volume with steps that allow good adjustments. I'd suggest you start by auditioning these, however, I bought the Pass XA 60 based only on what I read and am completely pleased. In fact, I bought the Joule based on descriptions on the internet...also completely pleased. Good luck with your new system.