Those who own S14’s with the factory CD player also have to deal with the factory installed Clarion amplifiers in the trunk. The existence of these amplifiers make installing an after-market stereo somewhat of a pain. Since the amp is made by a name brand and tuned specifically for the factory speakers, it’s actually in your best interest to leave it be, even if installing an aftermarket head unit. When doing so it’s advised that you use the pre-amp outputs of your head unit and NOT the speaker outputs that normally connect to the factory harness. You’ll want to look for an “amp integration” type harness when utilizing the factory amplifier and not your head unit’s internal amplification.