Car manufacturers are now offering car alarm systems with their cars. However, these car alarms often do not provide adequate security. To be more certain that your car is protected, get an aftermarket alarm.

1. Check out magazines that cover car alarms, such as Auto Sound & Security and Car Audio & Electronics. Get an idea of what kinds of features different alarms have.
   
   
2. Contact well-known manufacturers of car alarms and ask for product literature. Top companies include Directed Electronics, Clifford, Crimestopper, Alpine, Omega Research & Development, Avital, and Code-Alarm.
   
   
3. Determine which features your car has that match it to an alarm. For example, if your car does not have power door locks, you won't be able to use this feature with an car alarm.
   
   
4. Consider how you use your car. Do you leave things of value in the trunk? Do you travel in the car alone at night? Do you park your car outside? Your evaluation will help you choose an car alarm with the features you need most.
   
   
5. Make a prioritized list of features you want in a system. Use the list to question a salesperson about features of particular alarms. If you can't afford the perfect car alarm, eliminate features one by one.
   
   
6. Choose an car alarm from a major manufacturer, which will probably have dealers around the country in case you have problems on the road.
   
   
7. Ask about manufacturers' warranties and the shop's labor warranties.