Saw your (older) post and wondered if you did this, as I'm considering this on my 2002 X5 3.0 d (I live in Switzerland).

From what I can see, it's fairly easy - assuming you have the RDC button near your shifter.

Install module in the fusebox area.
Install antenna's in the wheel housings (TIS shop manual shows removal for front & rear, I think the front one goes on the left front housing).
Install the sensors / valves in your tires.
Initialize (there is a small video on Youtube from a fellow in AUS).

Did you finish your install?

I've added front & rear mud flaps (easy), PDC (not too complicated) and the front seat first aid kit & fire extinguisher.