How many of you upgrade your preamps and amps?

I was just wondering how many people have upgraded their equipment by a non factory tech. I have recently upgraded some older equipment with very good results. I also presently have a Accuphase P300 amp that will have the electrolytics replaced with black gates and Mundorf M-Lytic caps installed. With the higher cost of great seems to be a excellent way to go.
I urge you to contact the service dept. of Accuphase. I have installed many simple capacitor and other parts upgrades but I always contact the service techs for their advice. Often they know a bit more about their stuff than you can figure out for yourself.
I have a factory upgraded Accuphase C200 and a C200 that my local tech upgraded. The private upgrade is about 10X comparison. The original used elna caps...I had Nichicon gold installed. I am lucky as my local tech was a trained Accuphase dealer. On the C200 there are about 22 caps that need to be changed out or bypassed in the sound path. Also the noise floor can be lowered significantly.
Pretty important difference between "non factory tech" and "my local tech was a trained Accuphase dealer".
Samujohn.....I guess my point was that the factory tech doesn't have the descretion to make changes that would void a warranty. At this point for me that's not a issue.

As an example my tech called today about my P300 Accuphase...the Mundorf M-Lytic caps 47,000uf 80V will fit the he machined the sheet metal covers for clearence. These caps are expensive at 130 bucks a piece but they are exceptional. So my P300 upgrade should be magnitudes better than a factory spec amp. For $600 spent the amp should approach class A performance.