I will be doing this but you need the Bose system and amp + all speakers and the loom.
I have the loom and all I am going to do is cut off the door sockets from loom and extend the door wires so they are same length as the front to rear wire that goes from head unit to amp in parcel shelf beside sub.
Then I bought an iso socket with short speaker wires already attached. So will attach this to the speaker wires that come from Bose amp that I extended.
This will mean I will have two iso connectors one a socket and one a plug all the same length. It's just a case of installing Amp, sub and door speakers, then lead Bose loom from amp under rear seat, under carpet in centre into the centre console behind handbreak, lead it along inside there and up behind head unit. Then it's just a case of plugging the Bose iso socket into head unit and the speaker iso that was removed to plug in the Bose goes into the iso socket I wired up. This means it will use the speaker wires installed in the car already.
Sure there was a retrofit Bose guide in the ice section of here with pictures etc. of an install done in exactly this way.
Hope it helps