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 WarningEngine Overheating
There is an engine coolant temperature gauge on the vehicle instrument cluster
to warn of engine overheating.
If the decision is made not to lift the hood when this warning appears, get service
help right away.
If the decision is made to lift the hood, make sure the vehicle is parked on
a le ...
Thread Inserts
General Purpose Thread Repair Kits.
These kits are available commercially.
Repair Procedure
Warning: Refer to Safety Glasses Warning in the Preface section.
Note: Refer to the thread repair kit manufacturer's instructions
regarding the size of the drill and tap to use. Avoid any buildup ...
Installation Procedure
Cut the roof front header 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 portion of ...