Where can I start to improve my sound the most 2ch

Room acoustics is very important. It will make more difference than cd players, wire or any ss electronics. Without good acoustics you're not hearing your system as well as it could sound and this is commonly quite an ear opener. For the money it's a bargain compared to what many of us have in our systems. Bass traps can other room treatment can be made rather inexpensively too. I'm sure many of us here would like to hear what you think after you get some room treatment. Fair warning: Once you start and hear how much better your system sounds it's hard to stop.