Most people can't hear differences beyond speakers and tube/transistor, if that. Don't spend any more money on tweaks for a good while. Speakers, yes, but wires no. You've got good stuff already. Relax and enjoy it. Put your energy into finding recordings that you like.
I've been into audio for about 50-years. The refinement of my listening skills has grown through a series of epiphanies. I started with a great intergrated tube amp by Scott and really clunky Jensen speakers, next came DCM Time Windows, then Bryston electronics with Celesion cab, etc. etc. I'm in the middle of my fourth major reconfiguration in 50 years. (Getting back to vinyl).
Being a serious amateur musician helped me, but I've known many successful musicians with poor listening skills. Over the last 10-years I've written equipment reviews for Just Jazz Guitar, including a relative infamous guitar cord and speaker cable shootout. Like playing basketball, practice helps a lot. It's not all about natural ability. There's lots of training involved.
Being able to hear small differences adds to my enjoyment of the hobby, but it's nowhere near the enjoyment that the music gives me. Without the music there's no point in the hobby. Don't let people prey on your insecurity. Just figure what you want to spend and stay on budget. People will often say to me something like, "I really like what I hear in your system, can you tell me what to do?" I find out their budget, make some suggestions and perhaps steer them to a trustworthy dealer.
Dave