was it the same year? in theory i would have thought you could do that, but if you dont mind paying a tenner from halfords you can match the wires as they say what each wire does, but ideally you would want a voltmeter purely to find out where power is coming from i.e ignition live (red or brown i believe) and constant, (yellow)
i think they will be the same colours on a mark 3 but dont quote me on that, so basically you should have a power switched and constant power and a live to get the stereo working. If you dont mind the stereo coming on wothout the ignition you could just join the constant power and switched wire from the stereo together making it easier, hope this all makes sense! then of course the speakers would need wiring in. But hell yeah if you can find the right iso in the scrappy by all means just fuse them together, ther will be other wires like orange for ilumination and poiwer antenna which you probably woint use.
