I'm kinda a newbie to this kinda stuff, but I was wondering about putting in rears behind the seats, however, I already installed new polk components into the doors with a Alpine 2 Channel amp into my Alpine 9856 head unit. Good news is, I bought the amp like two weeks ago so I can still return, however, to run the rears can I run it directly into the head unit, or would it sound horrible???

Thanks everyone.

 

I run JVC 4-ways in the doors and used the original stock door speakers in the rear panels. By tapping into the unused second channels of the stock head unit, you effectively double the wattage output of it. I'm not an audiophile and this set-up has worked well for me for nearly 5 years.
The second stock channels do not mute when you push the button, but if you get Lucid's rear speaker harness, the full mute function is retained PLUS it makes it much easier to splice the rear speakers into the back of the harness. Otherwise, you have to deal with tiny little raw output pins if you have an early model S2000. The later ones with the optional headrest speakers had wires hanging out for the 2nd channel.
Of course, you can get real fancy speakers for both the doors and the rear panels.

Oh, this might give you some ideas:
https://www.s2ki.com/forums/showthread.php?...er%20userid1612

 

thanks X!!!

 

S-Pods are another option for rear speakers, and can be seen at: www.streetsmarttechnologies.net