Sub Amps and Generators

Keep hearing cheap amps (especially chinese copies) will not survive Generator "irregularities" as well as as quality brands like Crest, Crown, EV.

Any comments?

Do expensive distros have over voltage protection on power inputs?

I've searched for an heavyweight stabilizer but I can't find a suitable one. I was looking for material to build one but a cheap amp....and only the material for stabilizer cost so much than a 2nd hand big brand amp.