I am looking for a replacement head unit cuz some of the buttons on the factory one aren't working anymore. One thing i noticed in the different specs was the peak watts. What does this mean? what is a good peak wattage for good sound? What are other signs of a good head unit?

 

If they say Alpine or Pioneer on it.

But seriously peak wattage is the worst thing over to go off. If your looking for something to power your speakers better then the stock headunit look for one with higher rms watts.