OK, now that I have the Caddy at home it's time to make it mine, a few special little add ons and I'm fitting a tow bar and the fella tells me it has to have a special wiring harness (I guess because of airbags etc) but I mentioned to him that I was going to put somer LED light strips in the back to increase the lighting to a reasonable level (inside the car) but he tells me that I can't just splice them into the wiring as it may affect the computer, sounds a bit crazy to me but what do I know? any opinions.

just run a power wire to the + battery with a fuse in itt and a switch to turn lights on and off , just like in all the campers or tradies vans / utes.

Morgan did it on his late model t5 4 motion. From memory it was spliced up near the fuse box so the computer didnt detect the voltage drop. Ill find out for you. Or pm him. he is traveling around OZ at the moment so is a bit hard to get hold of.