Upgrading

Speaker wire, interconnects, and skip the power cord change. 

I'd do power cords 1st

It would be really helpful to see your system… you can put photos under your user ID: your virtual system. This allows us to help. Without us knowing your system it is hard to make educated recommendations.

I have been at this for fifty years. My current ranking of importance would be 1) speaker cables, 2) amplifier power cord, 3) other interconnects, 4) other power cords. But, your components mater… the venue (do you have direct power lines?… etc is important. More info would be helpful.

Remove sighted bias and all wire sounds identical. Have someone help you do a blind listening test. You will be surprised by the results!