What are the weakest components in my system?

A chain is no stronger than it's weakest link. If you are a real music lover, and you have the available means; I suggest you make a comprehensive plan to start all over, however, the amp is the heart of the system.

I also agree that probably your HK is one serious weak link in your system but I am also surprised that no-one has mentioned the speakers. Despite what Orpheus 10 said about the amp being the center of your system the speakers are the heart of your music. You do need a balance between source components and speakers but I have seen time and time again systems where a simple change of the speakers made a huge difference in the sound and the enjoyment of music.

For now disregard any advice regarding cables and dedicated electrical outlets. These things should be looked at after the overall sound of your system is satisfying to you.

The worlds best speakers will give you "Crappy" sound if you have crappy electronics; however, you can get boss sound with decent speakers and boss electronics. It should be possible for you to audition electronics before you commit, that way you can tell how much improvement you get from an upgrade.