Hi, so I wanted a trem on my les paul epiphone I found stetsbar and Schaffer trems not requiring any wood work or cutting but what I want to know is are they hard to setup and will they cause any buzzing or bad sound

I personally wouldn't bother with those sorts of systems because I hear they suck. Horrible tuning stability and poorly designed.
Quote by Axelfox
Haven't used the Schaller (assume that's what you meant) but the Stetsbar blows. Most of the aftermarket LP trems are total garbage. Something a little more serious like a Bigsby or a Kahler works great, but half-assing it with a drop-in stopbar trem usually yields bad results.