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 WarningInstallation Procedure
Remove all mounds or loose pieces of urethane adhesive from the
pinch-weld area.
Inspect for any of the following problems in order to help prevent
future breakage of the window:
High weld
Solder spots
Hardened sealer
Any other obstruction or irregularity in the pinch-weld fla ...
Towing the Vehicle
Notice: Incorrectly towing a disabled vehicle may cause damage. The
damage would not be covered by the vehicle warranty. Do not lash or hook to the
chassis components including the front and rear subframes, suspension control arms
and links during towing and recovery of a disabled vehicle or t ...
Rear Bumper Impact Bar Replacement
Preliminary Procedure
Remove the rear bumper fascia. Refer to Rear Bumper Fascia Replacement.
Rear Bumper Energy Absorber Nut (Qty: 6)
Caution: Refer to Fastener Caution in the Preface section.
Tighten
40 N·m (30 lb ft)
Rear Bumper Impact Bar
Special Tools and Equipment
...