Denon AVR vs. Martin Logan Electrostats

My main speakers are Martin Logan "Source" (ESL electrostatic panels) added to a system powered by Denon AVR-X3000. Previous main speakers were Martin Logan SLM-XL (part of the Motion series), and volume was fine. Now with the ESL's, the AVR can't deliver enough volume, and because of the low impedance of these speakers, fear the AVR is struggling with the load. Martin Logan website recommends using 'quality' amplification, which they define as, "...nearly doubles power from 8ohm to 4ohm load, and doubles again to 2ohm load...". Denon says their "X" receivers nearly double power between 8ohm and 4ohm, but no mention of 2ohm (so I suspect 4ohm is their limit).

My question is, will an upgraded Denon AVR with more power (AVR-X4500H, or 6500H) supply the needed power to get the most of these Martin Logan's, or is a pre/pro required.

I am a fan of the Denon feature set (for HT), and have thoroughly enjoyed the X3000 for many years, so wouldn't mind upgrading if that will fix the problem. But anything above that (cost-wise) or loss of features is not the direction I want to go.

If Denon doesn't offer an AVR that will push these ESL's, then I'd rather replace the ESL's with something else. DefTech is out (can't tolerate the shrill sound of those aluminum tweeters), and I know from the Martin Logan SLM-XL's that I really like AMT tweeters, and am perfectly ok with any good soft dome. Most likely speaker substitute would be either Golden Ear (which I have auditioned - they are awesome and awesomely expensive) or Emotiva (which I have not heard) - both have good reviews. I have also heard Martin Logan Motion 60XT, but was underwhelmed (too bright and with cabinet resonance when pushed). 

Any thoughts would be appreciated. Hoping others with ML ESL experience could tell me straight if Denon AVR-X**** just won't deliver, and I need to go speaker shopping. Will be tough giving those up, if that's the case - these electrostatic speakers are truly amazing (even when underpowered).