Building a system that gives you what YOU want out of the system is a long term project that results from first deciding what you like. That means developing the capacity to hear in your subconscious the way you want to hear it. Then you try out different components, to include power cords and interconnects, that get you step by step to the sound that you are imagining. No one can tell you in advance exactly what choices are going to get you where you want to go. There is no substitute for trial and error. Once you get a semblance of your imagined goal, you still trade out bits and pieces for those last few percentiles of what it is you are after. So, in my opinion, no one can tell you where to start upgrading. Do it yourself.
