The only concern you are going to have is with power. You know the distortion that you get when you turn the volume way up? That's most likely from the internal amp in your headunit clipping (assuming you have a new car, with half decent stock speakers as most are). It is because the speakers aren't getting enough power. A stock headunit is probably putting out about 5W, while that Nak would put out about 12W at a reasonable THD. Don't listen to their wattage ratings on any headunit as it is usually at about a 0.8%THD@rms on a headunit as opposed to about 0.02%THD@rms on an amp. They crank them up until the distortion is much higher (40X in this case) to get a more impressive wattage number. Most people skip by this fact. The difference between 5W and 12W will be noticeable and probably enough to satisfy most listeners. But, if you install power hungry speakers or like it really loud you will need to go with an external amp. Good luck.

Mike Cousins
#14979 on the waiting list