Sometimes, you just obligation to crank up the volume. Car audio systems must overcome a good deal of ambient noise--a vehicle traveling down the highway in the company of other loud engines is surrounded by a grand Car Amplifiers background blast level. Factory-installed head units have a modest amount of amplification (generally about 10 watts per channel or less), and bounteous aftermarket head units have at least twice that.
The aggrandized power the amp included with your CD or cassette player delivers, the cleaner the sound from the speakers. But be careful--a receiver rated at 50 watts maximum talent probably old-fashioned no exceeding than 20 watts of clean power. For that reason, serious mobile listeners eschew the modest amplifiers built into head units and instead opt for powerful external amplifiers.
How to Shop