Buy your own tuner. It's the most cost-effective way to keep your engine from blowing up. Then, headers and a Borla cat-back will make it sound the best it possibly can, maybe do rockers or a mild cam. Anything beyond that and you will probably need a built trans, unless you drive it like a granny and never go past 50% throttle. These are decently quick cars, but they aren't fast cars.
Keep it mild, and keep driving it for a few more decades.
Focus more on ride and handling, looks, and comfort. Those will be what you will enjoy the most in a car that you drive every day.
