Opinions about upgrade

spitzer45,
     You're on the right track by listening to various speakers to find out what you like and don't like.  Discovering you like the ATC midrange is good progress.  
     I'd suggest asking that dealer if you can take a pair of ATCs home for a few days to audition with your amp in your room.
    I'd also suggest taking your time on your search and resist the urge to buy until you do fall in love with a pair of speakers.

Tim  

The ATC 40 passive are not easy speakers due their very low sensitivity (85dB) I suspect your Hegel will not be able to drive them properly .I storngly recommend you to give a chance to the Proac D30RS, they are very special speakers once you hear it’s easy to fall in love with them and are very efficient and easy to drive.their ribbon twitters are one of the best I ever heard the special innovative pulp and mika massive driver deliver transparent natural mid and powerful yet very control bass.

Hello again, I pulled the trigger and bought Atc scm 40 passive version. After proac d18, it was really a nice upgrade for me. Especially bass resolution, soundstage and mid performance impressed me. But trebles was a bit roll off compared to proac d18, maybe after some hours it will be opened up. So far so good.