Single-part underbody protection (E90/E91/E92 AWD)

Release screws (1).

Remove underbody protection (2) downwards.

Installation: 

Ensure correct seating.

Centre underbody protection (2) and tighten down screws (1).

Fig 1: Identifying Centre Underbody Protection And Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Two-part underbody protection 

Release screws (1).

Detach underbody protection (2) from bracket (3) and remove.

Installation: 

Ensure correct seating.

Centre underbody protection (2) and tighten down screws (1).

Fig 2: Removing Underbody Protection From Bracket

Courtesy of BMW OF NORTH AMERICA, INC.