Has the car been on an alignment rack recently? Most shops will charge a small fee to check the alignment without adjusting it(my shop is only a half hour labor verse 1.8 hours with the full adjustment FYI). It also looks as though they're pretty well worn out just more so towards the edges. Take what Mafix said to heart. Owning a sports car(especially one thats 20 years old) requires constant small checks to keep from creating expensive problems. Tire pressure is number one on that list. Remember that your tires are the only thing connecting you to the road. Keep your pressure around 35 psi and rotate the tires every 3000 miles. Have an alignment check done at least once a year. Its amazing how fast poor alignment angles can destroy a set of tires.
Good Luck,
Allen