Tube Amp, Preamp upgrades -- what did you do that improved your units?

When I rebuilt my Dyna 70s into VTA 70s, I added the VTA board, new power supply caps, fresh tubes throughout, and premium caps in the audio stage.  The biggest changes since then have been from rolling tubes.   I settled on RCA clear top 12AU7 driver tubes, 12BH7 in the center and Gold Lion KT66 output tubes. 

Some vibration isolation can't hurt.

Some vibration isolation can't hurt.

Put springs under the amp. Plenty of threads here on the subject. 

how are your soldering and de-soldering skills @hilde45?  important question...

@sns 
Thanks. Helpful advice regarding replacement parts and possible breakages.
"What is the sound quality you're looking for?" -- a good question. I'm not sure but I've heard that more air and detail are possible. Sort of like the question "Why would you want to try better beef?" Not easy to answer without experience. But you're right to look to other users.

@dekay I chose this pre because I didn't want a remote volume, so not going to alter that.

@decooney I have found an expert here in Colorado. No worries about his work.

@russ69  I suppose I could call Mike, but might he just defend his amp/preamp as built? I can understand that, but perhaps not objective enough?

@knotscott  -- I've been rolling tubes, too, and appreciate the KT66 mention. Want to try that; love the KT77s.

@jjss49  I would not do this myself. I'd pay to have it done and pay to have it reversed. Just like a vasectomy.