everyone removes the factory amp because it is crap, it puts out about 5 watts rms of dirty sound. most head units have better amps, so people use that instead or an external amplifier
i didnt have an amp to bypass, but from what i can tell you just need the amp bypass harness, i'll let people w/experience with this answer this tho
but honestly i would cancel the install and do the whole thing yourself
its a little confusing the first time but after a few times you can remove a factory deck and install an aftermarket within 20 minutes if not quicker
i installed my first one when i was 16, paying someone to do it is just a waste of money. you just gotta be careful and take your time
