Need upgrade advice

Maybe you should try Linn Keltik speakers...i know people "swear" on the Magneplanars but still,... i would try Keltik's with majority Linn gear. Also you can go "aktiv" in the future...something to keep you occupied.

You have a well balanced system. If you want to improve the system you will probably have to upgrade as a system and replace most of your components. Rather than replace any components, explore careful system setup (speaker position, clean connections, dressing your cables, etc.), room treatments and/or a high quality equipment stand. Beware of spending big bucks on interconnects/cables/power cords. These products can make a very positive difference in a system, but most audiophiles over spend on these items.

What kind of cables are you using? I would recommend NBS, I am a dealer so let me know if you want more info.