Seems nice, although 50W may seem a little short for the front speakers. Well, depends on what you want. For most, that's really enough.

MY last car I had about 45W to each rear speaker, and ~120W to each front speaker and also to a pair of 10" subs. I thought it sounded great, they all had the gains set about the same, and ran out of power at about the same time, which was at an uncomfortably loud volume.

I like it louder than most though. I don't go booming down the road and I make sure to not disturb the neighbors. But on the freeway coming into work or going home, it's up a few notches louder than I think most people would want it. Personal preference I guess.

Rule of thumb, historically, was double the power to your subs as you would to the front speakers, and double the power to them as you would to the rears. This is old school though, 10 years ago when I was really into it more. I still like the fronts to have more power than the rears (if I can tell the rears are making noise, they're too loud for me - I like almost everything to come from the front). The subs to me can be about the same as the fronts though. Unless you like rap...