Quote Originally Posted by AmateurJazz View Post
Check whether your stock headunit has RCA ins (most likely it won't) - without any RCA ins you cannot hook up your amp to the headunit. You will need to get a converter/FM modulator like fr3aki3 said, which converts the speaker cables into RCAs. That connects to your amp and the rest is just like usual.

Bear in mind that with this setup the sound is coming from a frequency from your radio and hence quality will not be optimal.
BS ALERT!!

Seriously, you ain't got the foggiest. RCA INS are, as you would expect, for putting a line level signal IN to the head unit. Such as an iPod signal.

We're talking OUT as we want signal out of the headunit. As someone already correctly stated, there are no line level outs (RCA or otherwise) on the stock head unit, but there are two sets of speaker level outs not used. They are for rear speakers and the S doesn't have any. You'll need some pins or a connector from another Honda car to connect these to the 'Speaker Level INS' of most consumer grade amps and play your doof-doof to your hearts content (although not your ears or neighbours).