Unfortunately, any head unit is not producing 40-60 RMS [true power output]. It is more like 15-24 watts RMS. Like said above, it will be weak then as well. Depending on the nature of the beast, you can use a after market deck if the components are on the entry level side, 50-75 watts RMS. Now if you buy a 4ch amp that is in the 35-100 watt RMS range you will have a nice clean and loud audio. I sold super high end car/home audio/video for many years, and I can tell you that hands down ALPINE is the best!!!!!! Audio processing is far more superior to the rest. Just google alpine F-1 Status [ nuff said ]. The deck I have sitting in my closet is one you can get pretty cheap these days used. Alpine CDA-9813 - Alpine CDA-9815. It is a highly complex unit, but it is clean,clean,clean!!!!