no it will not be the same as there are no hu that do 50w rms that I know of thats a peak rating and unless you bought a crap amp it's most likely an rms rating so the difference is instead of 15w rms from a hu you will have 50w rms coming from an amp.If you have a 50 x 4 head unit and you install a 50 x 4 amp is it still 50 x 4 going to the speakers?