Investigate changes in sound or performance: don’t let little problems become big ones.
Follow the Maintenance Schedule in the Owner’s Manual.
Don’t waste money on things like “induction service” or various flushes, however:
Change all fluids periodically. I recommend:
Transmission fluid: drain and refill every 30K miles, change the filter (if applicable). Use only what Pontiac specifies, no “universal” stuff.
Brake fluid: change (bleed) every 3 years.
Coolant: change every 5 years; change the thermostat and radiator cap.
Power steering fluid: drain and refill the reservoir every year or two; an easy DIY job.