How big of a difference do amps make?

The tube amp makes a huge difference, the preamp second.

I've gone back and forth from tubes to solid state many times in the past 40 years and now have both types of systems. Is one better than the other in most ways? Nope.

polk 432
So in your experience the tube amp made a bigger difference than tube pre?

Case in point, in 2002 I purchased both a Krell KCT preamp and 300cx amp from San Francisco Stereo to power my Thiel CS6s. After half a day of listening I decided that perhaps the more powerful 400cx might be a better match, so I swapped out the 300cx for the 400cx and immediately, I heard more detail, deeper and more highly controlled bass, and deeper soundstage (yes, the 700cx was way out of my budget then). My point here is that even within model lines, and given all else equivalent from a design and execution standpoint, the power supply itself and the current served up to the speakers can make a huge, audible difference.

point could be taken that even amp of less quality with sufficient power may sound better than great one with lack of power.