I've just finished fitting a set to my 2005 Touring (E91). A few points which might help others:-
Only initially remove an inch or so of the adhesive strip backing (2 runs per flap) leaving the backing sticking out until you have finished all the bolting up. You can then pull each run of backing out and press the flaps hard upto the body. This allows for much easier positioning.
There is no need to separate the two section of each rear mudflap. Just fit them as they come.
If you buy from a BMW service main dealer, ask them to print out the relevant instructions from their Aftersales Assistance Portal (ASAP). They are supposed to ask if you want them anyway.