I have always offered this advice - only you know what you like and if you like your system the way it is then listen to more music.
We are manufacturers and we often tell customers that if they don't hear a big improvement in the first 30 seconds then simply sent the unit back to us.
We also do upgrades and modifications which to our ears can make a dramatic sound improvement without spending mega dollars on a high end components in direct comparison. What makes one amplifier sound better than another one. Usually not the parts inside if at all and not the price.
Only you can be the judge of a system upgrade. But you also need to know what makes sound better in the design of a product and how that design is implemented. In general, most people have no idea why something sounds better or different. I love it when someone says built like a tank but they have never built anything in their lives.
Happy Listening.

