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 WarningReduced Engine Power Light
The reduced engine power light should come on briefly as the engine is started.
If it does not come on, have the vehicle serviced by your dealer.
This light, along with the malfunction indicator lamp, displays when a noticeable
reduction in the vehicle's performance occurs. Stop the vehic ...
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
...
Braking
Braking action involves perception time and reaction time. Deciding to push the
brake pedal is perception time. Actually doing it is reaction time.
Average driver reaction time is about three-quarters of a second. In that time,
a vehicle moving at 100 km/h (60 mph) travels 20m (66 ft), which co ...