Maybe this response is late, but I also have the Acurus ACD and "had" the 1.5 qr's with a SUMO Polaris II amp. The similarities with your system were spooky. I said "had" because I was bothered by the treble as well. I think your choices are great but think I have some experience with these components (I have also owned two Hafler pre-amps...the list goes on and on..)
Write back...I'll let you know what changes I made that led me down a slightly different path and perhaps I can suggest some things which may improve your already nice system.
PS...my current system cost less than 3000 bucks and the preamp was over 30% the cost..