I'm currently in the process of installing an avh 2300nex into my car and just removed the factory stereo. but I'm confused to if I should use the pre amp out puts or no, because the speaker do work if I connect the power supple wires to the stereo and the seem fine.... I don't wanna go into too much of a hassle if its not worth it …. am I not getting the amped sound just through the wiring harness???...sorry if it sounds a little confusing this is my first ever install..Thanks