For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningFront Side Door Adjustment
Preliminary Procedure
Remove the front wheelhouse liner. Refer to Front Wheelhouse Liner
Replacement.
Front Side Door
Caution: Refer to Fastener Caution in the Preface section.
Procedure
Loosen the front side door hinge bolt (Qty: 4) to adjust the front
side door.
Adjust the ...
Installation Procedure
Cut the body lock pillar outer panel in corresponding locations to fit
the remaining original panel. The sectioning joint should be
trimmed to allow a gap of one-and-one-half-times the metal thickness at the
sectioning joint
Create a 50 mm (2 in) backing plate from the unused portio ...
Navigation System
If the vehicle has a navigation system, there is a separate navigation manual
that includes information on the radio, audio players, and navigation system.
The navigation system provides detailed maps of most major freeways and roads.
After a destination has been set, the system provides turn-b ...