Yes, i searched, but im looking for specific answers. Ok, i have a head unit im going to install on my 92 sc400, i've heard about having to rewire to the amp so the speakers/sub will work, is this a thing ALL SCs need or is it just some cases? im going to be using stock amp and speakers, and if i must rewire the head unit, how hard is it and what is the cost?

 

you should be able to get a hold of an amp integration harness for your vehicle. it should work with whatever system you have in there. it will use the factory amp still, but you may lose your sub...

 

how can i keep the sub? im not going to do this if i lose the sub

 

add an aftermarket amp to power the factory sub. doesn't have to be big. or just put in an aftermarket amplifier and sub.

 

The only way that I know of to keep the factory speakers and replace the deck is to wire the speakers directly to the aftermarket deck which will make you lose your amps, both the regular and sub, and the sub itself as well. If you try and wire it to keep it all as factory as you can, you will get an insane amount of engine noise through the speakers (search for that and you will find tons of threads about it).

I have never seen anyone be able to keep the factory sub w/ an aftermarket deck. It's a pretty crappy sub anyway, so its much easier to just replace it with a quality one anyway. For my needs, I ripped all the factory stuff out, amps, wiring, everything and have the deck powered by the factory wiring for the stereo, but ran all new wiring for all speakers and of course two amps and a sub.