More power always seems to sound better to me. Going from stereo deck power to 60watt amplifier makes audible difference. Going from 60 to 120watts once again makes a difference if you have good ear. With a better amplifier you should hear tighter and more dynamic sound that can also be played louder when necessary. The only issue is try to avoid crappy bargain basement amplifier brands. Jensen, Boss, Dual, and a few others. Even if they do the rated power, a lot of those amplifiers are simply audibly noisy and have poor build quality. Also 50watts RMS is not a lot. This is plenty for a coaxial speaker, but if you upgrade down the road to something else, this may be only adequate.
Ideally you should have good amplification and sound proofing, at very least in the front doors.
