Solara Stock Premium sound system

Thanks wvsquirrel for the kind words.The main reason I often suggest using an external line output converter is that for some vehicle's the factory output voltage is higher than what the aftermarket amplifier can handle, even on its high level inputs.  The external converters usually do a little better job of handling that higher power, but they're not required for all vehicles.  Might want to check out this rockford fosgate article.  As they point out, a few vehicles have systems that put out more than any internal or external converter could handle.

One other thing, and this might be a rumor or it might be true, but....I have heard from some people that using the high level inputs on some aftermarket amps can cause the speaker impedence to drop to levels unsupported by the stock head unit.  Again this is merely a rumor and I've not personally experienced it, but to be fair I never use the built in inputs anyways so I wouldn't really know.  I haven't heard of that problem for a couple years now so maybe it was just something with older technology.