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 WarningVehicle Identification Number (VIN)
This legal identifier is in the front
corner of the instrument panel, on
the driver side of the vehicle. It can
be seen through the windshield from
outside. The Vehicle Identification
Number (VIN) also appears on the
Vehicle Certification and Service
Parts labels and certificates of title ...