#1
Had this done for a while now, but man, it was so cheap and easy if you can solder well. I swapped out a few values of the caps and resistors, and ran it through my 412 cab slightly attenuated. This is the mod I did:

http://www.300guitars.com/articles/hot-rodding-the-new-fender-champion-600/

It sounds wonderful through a 412, but even on its own with the small stock speaker, which I haven't gotten around to changing out yet, still sounds great.

Here's a clip of it

https://soundcloud.com/cwheeler22/fender-champion-600-hot-rodded

I think it was about 3/4 volume when I recorded it. Very usable amp now, no more farty tone. Only costs like 6 bucks for the parts, and the amp can be found for cheap too.
Agile AL3000
Douglas WRL90
SX SR1 STD Plus
J&D Strat
Squier Tele
Sammick TR2
Douglas Draco
Peavey JSX
Bugera V5
TWANGED VJ
#2
Nice man, I like that site. I'm in the process of building a VibroChamp and am eager to tinker around.