Sounds to me like audio fatigue. Try to forget about audio and demming, and all the potential variables for a while. Go and do something else, then come back to your system with fresh ears. I think we all suffer from this from time to time. Don't spend any more money, and don't sell anything (at least not yet). Let your brain recover, lose the "itch", come back in a month and hear how it sounds. When you do, listen with your GF. She probably has better hearing than you (or I), and if it sounds good to her, then it probably is good. Throw a party, invite some (music loving, but non-audiophile) friends round and bask in their admiration for the sounds. Upgrading the mind is the cheapest and by far the most effective tweak of all. And eventually, when the time does come for a change (as it does for all of us :D ), do as Titian says, work out what your priorities are first, and take it from there. Just my thoughts for what they are worth.