hi everyone....i'm kinda new at all this thing....i've looked into changing out my stock HU with an aftermarket....i have an 03 touring edition with the bose and navi. I try to put in an new HU but i got no sound coming from the new HU....i can't figure that out....so what i wanna know is can i remove the factory amp and replace it with an aftermarket then just wire the new HU right up to the amp and speaker.....i don't know if the Navi will interfere with the HU....i got the NAVI wired up to a different speaker by itself with a relay and all. From what i seen the Navi is its own system....doesn't look like it will interfere with the new HU.....also how would i wired up the aftermarket amp inplace of the factory amp. i know i have to remove the two front speaker.....do you guy think that the amp might mess my car up? HELP ME PLEASE