John,
Given the kit that you already have, I doubt 5k would bring a jaw dropping improvement. That is unless there is a particular area that you are unhappy with or you have weak jaw muscles.
I have the same amp as you and one of those monster wadia things as you put it (not exactly an original idea I admit). I think to get the full benefit of the wadia you probably need to drive it directly into the amp. Given the rest of your equipment, I cant see you wanting to do that.
I would guess that room acoustics is an area worth investing time and money in. I know that there is great scope for improvement in my listening room to bring the sound above the level of merely acceptable.