BEST UPGRADE regardless of cost?

For me the big one was the source, bringing my Linn Sondek Lp12 TT home back in 1983. It all gets back to, if you can't retrieve it in the first place, you'll never hear it with even the coolest speakers or amplifiers IMHO. Happy Listening!

Merlin VSM-MM speakers,best single purchase ever,in my system ....

Build a dedicated Audio room. You've never heard your system until you've done this. Get Rives Audio, Auralex, or ASC to help you and follow their recommendations. You won't believe the differnce.

Shakti-sonic hollgraph's- After 30 years as an enthusiast, these devices are the best upgrade I've ever made. Makes one realize just how critical the room acoustics are-and may stop one from the "endless" componment upgrade path. They are just staggering in their ability to create a lifelike stage in one's room. C

The room. Design and treatments from Rives Audio made a tremendous improvement.