I think that your system is well balanced at the moment. So in my humble opinion, spending 3 to 4k on a component upgrade, might be just a slight improvement, but won't have me parting with 3k for that slight uptick.
So if it was my wallet and your system, below would be what I'd do :
1. The biggest singular night and day difference for me has been acoustic treatment. And trust me, it can be made visually pleasing with GIK art panels, and their bass traps for the corners. Once you have the panel mounted, just make your own gold frame to wrap the circumference of the panel, to make it look like proper art. Iam posting 2 pics of my DIY bass traps and my DIY gold frame borders.
( My room is still a work in progress, so what you see, is not what it finally will be
. Iam on a mission to build a aesthetically pleasing, treated room. I will resume work on my room in Sept, should have the finished results by November)
I just stuck gold tape I bought from amazon, on thin wood strips, and nailed them on the frames.
2. After room treatment, I would recommend townshend seismic podiums or isoacoustics gaia III under the speakers. In my own experience, the improvements in bass, mid range clarity and treble have been nothing short of a full speaker upgrade, but at a much lesser outlay.
3. If you do the room treatments yourselves, like me
, then room treatment + Isoacoustics gaia 3 can be done within a 1000 pounds. So that would leave 3k to improve your source if you wanted ( sell the aries 2 and get a terminator 2, or add a denafrips DDC like the gaia to the aries 2 etc ).
All the best