"General" amp mods & tweaks

Is there a section or an existing topic discussing general tweaks that can be applied to most ss amplifiers?

I have an Adcom GFA-5800 and in searching the Internet for info about it I ran across a couple photos of 5800s with bypass caps on the power supply rails & maybe on the output. Hard to tell from a photo not intended to be a "how-to" close-up.

Since I haven't had any luck finding mod info specifically for this amp, are there tweaks that typically get applied to virtually any mosfet amp?