When tubophiles wax on about how tubes completely changed their lives, brought them to a state of inner narvana and even made them better looking, you really need to dig into what systems they had prior or what they are comparing the tube component to. Tubes really sprang into popularity when most systems were mid-fi, at best in the 60’s to 90’s unless those audiophiles invested a fortune in one of the handful of manufactures making really powerful SS amps. So when comparing mid-fi to tubes it was definitely an improvement. You also would hear an improvement if you compared your current NAD integrated amp. My point is just that you should try some higher-end SS amps before you move to tubes because there are many more options today and many good SS preowned options.
PS. That impedance graph previously posted for your speakers is a deal killer. Don’t even bother putting tubes on those speakers. Tubes just don't do well on speakers that have an impedance graph that looks like that. They do best with fairly level impedance curves. Put a good SS amp with strong current on your speakers and you will notice a big improvement. Do you have a local audiophile club in your area? That is a good way to listen to higher end system.
