I'm planning on tackling this little chore at the weekend, when I've done it in the past I've either used an FM modulator which splices into the radio antenna connection or if the car has a sepreate amplifier unit ( as I think the GS300 does) it should have a pair of std audio connections so a simple switch box can be used to splice into the ampl input line.
any thoughts?
Where is the amp located anyway?
Matt
The amp is located in a bracket underneath the CD changer unit in the boot.
There are no standard connectors on the amp, just the factory connectors which are not RCA's or anything like that. You could splice into the "line ins" from the head unit I guess, although you will probably be bypassing the volume controlling of the head unit then. From what I remember, the cd changer feed goes to the head unit first, and then back to the amp, so maybe it would be better to ditch the changer signal and see if you can splice into that on its way to the head unit (assuming it is a line level signal of course).