Will a high quality preamp really make a difference in sound?? Also speaker cable

Common audiophile wisdom - active preamplifier is extremely important.

Speaker cables, like everything else, are important too. My speaker cables cost new or used as much as my speakers. Perhaps I overdid it a little but I haven't had to replace them in 25 years, and my system now sounds incomparably better than 25 years ago with the same speakers and cables. But it's a modest system, both speakers and speaker cables cost $1500 new 25 years ago.

Back in 1992 I purchased a AR SP-9. It made a huuge difference! It opened up the soundstage width, depth and detail. All improved immensely! It was though I walked into the room of the performance.

Put world class preamp in any decent system and you will probably agree with me. It is a transformative experience.   Makes the whole system sound better and live up to its full potential 

There are many great speakers out there hobbled by a mediocre preamp.  Or a so so amp.    Lots....  Part of the reason we've all been chasing better sound.  

 I think spending as much or more on amplification than speakers yields great results.  

More on amplification, definitely more. Unless the very top level where it might get equal, I don't know. Give any good speakers a signal and they will sing.

Right now I'm using 2 identical Anthem power amps MCA 225, NAD C379 preamp, Cambridge audio cxn100, and a Marantz single cd player as a transport using the dac inside the NAD. As far as speaker cable I'm using some that I found on Amazon and it seems to get the job done, the name of this speaker cable is WBC.