I looked at some of your recent posts and something seems to be getting to you about your current set-up. Have you been able to quantify that there is something missing from your system's sound or are you just torturing yourself thinking that there must be something that you can upgrade (like so many of us here)? Your set-up really seems OK (Adcom pre & power; Onkyo/PS Audio transport/DAC; Monitor Audio speakers) and I don't think that $350 will provide you with the "heads & shoulders" next level type of upgrade.
Regards, Rich