Good point. Should've said, if you do wire it that way & you leave your Landy for any length of time, disconnect the battery or at least anything that draws a constant (albeit small) current. I did that on my (proper) Mini when I was abroad for a few months, then got back to find I didn't know how to reset the immobiliser & couldn't find the CD player code ANYWHERE! So beware! You can always get one of those charger things that senses when the battery is in need of a charge & tops it up as & when............though that relies on the vehicle being garaged really........& they just kind of worry me. I expect to come home to find a blackened, charred wreck on my return!
Anyways, the long & short of it is, it's fairly straightforward to wire a CD palyer into a loom as simple as a series has, with a bit of thought & care.........isn't it?
Best,
Marcus.