
So I "upgraded" to my old Denon (radio cassette but has line in jack so I can be a bit more up to date) and JBL splits (yep - 4 inch splits !).
So, not exactly leading edge - but a big advance on the factory setup in my "bus station" car. I don't think anyone will try stealing a cassette either !
Must thank Suzuki for a din slots that is less than din size, and screwing the head unit in but showing extraction tool in the manual. Arrgh ! Forum search sorted that.

Anyway, I have found that I have an extra socket behind the dash which (according to the color coding) is wiring to the non-existent rear speakers.
My questions to oracles is - where would I find the other end of these wires ?
I did the obvious and checked near the grilles either side of the hatch tray, and also flipped the covers off the rear seat belts, but can't see anything there.
It would be nice to use the other two amp channels in the head unit. Yeah, it has 4 x "high power" channels. I *used* to spend money on Hi Fi. Then I got a wife and my ears deteriorated.
Cheers
Ian