Re: 147 bose sub and amp.!!!!!
on the 156 sw, there is a sub in the boot option, quite expensive, you need the sub and also the brackets to mount it.
But on the 156 the wiring is there, with a white plug on the end, you have to lift the carpet to find it as its taped back on itself.
It takes its feed from the rear speakers, probably a high output, the amp remote is fed from the head and there is pos and neg also. everything you need for factory standard.
don't forget the brackets, and you will/may need to cut the carpets.
thats the 156, don't know about the 147!