Unless you are in love with the electrostatic sound, you might consider a quality pair of moving coil speakers and stay with your electronics. You might use a variety of footers to "tune" the sound of the system from there until you hit the sound you are looking for. I have had great results from a combination of Black Diamond Racing puck/cones and heavy brass Mapleshade footers.
Upgrade amp or speakers?
I have Martin Logan Aerius i speakers, Classe Cp35 pre, Classe CA100 amp and Meridian 588 CD. I am looking to upgrade the pre/amp but don't want to spin my wheels ($$$) if the speakers are not worth the upgrade. the pre/amps I am looking at are the Pass x250.5, BAT vk-250 or ARC SD135. I tried tube ARC VS110 and loved the sound but it was a little too soft and moved music passages to the back. BTW, the speakers still sound great but am I over spending on the pre/amps? Thanks