Amp upgrade for Revel M20 speakers

For the past several months, I've been slowly upgrading my two channel system. Prior to that, I hadn't touched it in over 20 years. For all those years, it was: Denon DCD1520 CD player, Nak SR4A receiver, Spica TC-50 speakers. Today, with latest upgrade of speakers to Revel M20s, the system comprises: Arcam DV-137 (transport for CD, SACD playback), PS Audio Digital Link 3 DAC, Audible Illusions L1 pre, B&K Ref 2220 amp driving the M20s.

I'm pretty happy with everything at this point. At least I think I can finally stop the hunt for the right speakers - at least for a while. BUT....I can't help but think I can do better with my amplification than the B&K. The B&K is very nice but I think the M20s deserve just a little bit better.

There are two aspects of the current system's performance that I am looking to improve with a change in amplification: 1) wider, deeper soundstage and 2) more dynamic transients (I believe the B&K is a bit sluggish though not bad at all)

I have two options that I'm considering and am looking for input from people having experience with the M20s (or very similar). The two options are: 1) change out the B&K for another power amp (budget would be about $800 for used amp), 2) swap out the AI pre and B&K amp for a high quality integrated (budget would be about $1,200 for used integrated).

As far as amps to replace the B&K only, I really am looking for suggestions for something that would mate well with both the AI pre and the M20s and provide a significant improvement in performance.

Integrateds that I've looked into include: Creek Destiny, Nait Naim 5i-2, and Simaudio i-1. Any opinions on these or others in my price range that would give me the performance enhancements I'm looking for would be appreciated.

Thanks in advance for your suggestions.

Jon