Can't drive 55? You've got a fast car? You may have high insurance rates too. Because of their tendency to drive fast and subsequently get in more accidents, sports car drivers are often charged more than sedan drivers for insurance premiums. This is also because sports cars tend to get stolen more than other cars.
If you want to get a sports car, but don't want to pay high auto insurance premiums, wait until you're at least 30 years of age to buy one. Teenagers and twentysomethings are more likely to be involved in sport car-related accidents. Therefore you may have to pay more than you would for a sedan, but you won't pay as high a percentage more than your juniors.
Lowering other risk factors can help as well. Take steps to improve your driving record. Enroll in a defensive driving class. If you do buy a sports car, consider taking it out only on weekends, and using your non-sports car for your daily commute.