For the most part amplifiers are what they are, they either work as designed or they don't. It's not like a radio where you can do audio and swing mods and yield large gains. That said I suppose there are amp builders that have some tricks up their sleeve. I know Peakaboo used to do some work to Texas Star amplifiers. He would regulate the AB bias, add some caps, a fan system, and maybe heavier gage feed wire. I'm sure he did some other stuff as well. You will probably have to check with an amp builder.