What exactly do you want them to do differently? You could do a variety of things to them, either by adding something before the amp or by altering the amp itself. I would NOT recommend circuit bending these.
I prolly will be interested in doing whatever I can to the amps, puting something before the amp and altering it. do you know a web site where I can get some schematic or something like that?
Putting something before the amp is in effect just wiring an effect permanently in front of the input jack. Any effect will work. I don't know of any schematics of the amps you posted, but you could do a google search.