IF you are worried about setting off the air bag... (so was I) I had my dealer install my M3 wheel in my 135i. They only charged me 20 euros to do it. Probably took them all of two minutes.
IF you do the install yourself... just make sure the battery is disconnected and you wait an hour before working on the car. Also make sure your body/hands do not have any static electricity. Touch the chassis before working on the airbag connections.
Good Luck,
Dack