Adding An Amp To Factory Bose System?

Not all bose systems have the amps mounted directly onto the back of each speaker;  but I don't remember in this vehicle for sure whether or not it has a multiple amp setup or not.  I do think however that there's an amp in the rear left side panel, and this would either be a subwoofer amplifier or a single amplifier for the whole system.  Either way you're gonna need to get the signal for your line out converter from here.  It can either be a full-range signal or a low-pass signal; if all things are equal I'd take the full-range signal, but if it's easier to get at a low-pass signal (for a factory subwoofer for example) then you might as well tap into that wire.

Also remember that if you're using a LOC that you need to be getting a signal that's already amplified;  so that rules out tapping in to the back of the head unit.  Technically that would be possible though, but you'd need a line driver to accomplish that.