I'm looking at a switchable exhaust and have done a bit of reading. If anyone has an aftermarket one where did you connect the power wire ? The obv place would be the battery / positive terminal clamp in engine area but I beleice it's meant to Ben a switched live not permanent live.
I just picked up a feed from the cigarette lighter for the switch, then ran a 5 core cable from the switch up inside the O/S rear door card and through the rubber grommet into the engine bay where i used the air pump mounts to fix a waterproof box for the connections/solenoid. Didn't need all 5 cores, its just all i had to hand at the time.
I seem to have lost some pics of when i done it. It's pretty easy to do though.