rbuckenmeyer

In addition to the above responses, which are the tip of the iceberg of the technical aspects of the physics of sound, the amp will make major differences in the quality and quantity of sound, whether internal to a hu or a seperate amp. With regards to power, "clean" sound will be much louder than just more power. In other words, using half the power on a higher wattage (clean, well-built) amp will sound much better, and most likely "louder", than cranking up the gain on a smaller amp. Even though the "output" is likely to be similar if tested.

As stated above, a Jeep is not the ideal vehicle for a pure listening environment so I wouldn't get really worried about most of this stuff. Find quality components from a retailer you trust and have fun with your stereo. What's the worst that can happen... you end up replacing something!!! And that's fun to do.