I'm not a regular here on the X3 board, but I am over on the E46. I have a bit of experience detailing my cars and those of friends. Here are my recommendations...
Instrument Panel = Plexus Plastic Cleaner (properautocare.com)
Leatherette and Dash = 303 Aerospace Protectant (properautocare.com)
Leather = Zaino Leather Cleaner followed by Zaino Leather Conditioner (zainostore.com)
Armor-All supposedly contained/contains silicons that are bad for vinyl, which can induce discoloration. You should definitely take a look at Autopia.org for more information. Its a detailing enthusiast site, and I learned A LOT from it.