E46 bmw’s are notorious for the key lock on the door breaking. the only actual part that breaks in the cylinder is the second part installed on this video 13 seconds in.
Repair your busted door lock for a fraction of the price. Buying a new one at the stealership will cost over $100. these repair kits can be found on Ebay for under $20. It took me forever to find this video and without it it can be tricky to reassemble especially if you have taken it apart before your kit has arrived. Hope this helps. ENJOY