Personally I would do a thorough inspection, inside and out just to be sure that you don’t have hidden problems that could cause problems down the road but are easily addressed now.
-check torque on lug nuts and wheel hub bolts.
-verify all fluid levels and seals in the drive train
-have the coolant tested. There are tests that can be performed that will tell you if the coolant is still good.
-inspect the electrical connections. Battery terminals for corrosion, sample the fuses to verify general condition, pull up the carpet on the BCM and visually inspect it. Take a look at the front engine ground which has been a problem in a few cases in the past.
-clean and recondition all the rubber seals. Inspect them for condition, rips, etc. Apply the conditioning product of choice
-Do not forget to lube the driver’s seat electric height mechanism.
-Inspect the windshield wipers for condition and deterioration
-Visually inspect the tires for checking and any deterioration. If the car has been exposed to a lot of UV then the tires may be approaching their end of life. Check for missing or loose balance weights
-Visually inspect the exhaust system for leaks
-Visually inspect the wheel sensors for routing and condition
-Change the oil
-Cycle the DIC to verify all states come up and appropriate information is displayed
-functionally test the brakes, traction control if equipped and stability control condition and states
-Pull a GM vehicle maintenance report from the GM system and verify that all required maintenance is up to date and recalls if any are applied.
-Review the top fit issue and rattle issues and verify that your car does not have this problem