The problems I had with the Shure SE215, the bass was too strong imo. I was hearing more bass than the rest of the music sometimes.The Shure SE535 fixed all those problems, it's got a nice balanced bass, much better details and soundstage. I think this is a great improvement and I'm happy about these IEM.
What is spending $1000 or $2000 going to give me over the Shure SE535 in terms of sound? Will the difference be as big as going from the Shure SE215 to the Shure SE535? Or will it just be a sound character upgrade (a more flat sound for example if someone enjoys that?)