Is a built-in GPS worth the cost? May 31, 2008 With portable navigation systems running $150 to $500, should you pay $1,500 to $2,500 extra to buy a vehicle with a built-in GPS unit? Maybe. There are a few advantages to taking the more expensive route. RELATED LINKS Best Portable GPS Units for $300 or Less Home Security Goes Wireless Laptops: The Beauty and the Beasts Size matters. The typical big screen on a handheld unit is 4.3 inches. Stick a unit much bigger than that on a window or dash and you risk a driving hazard. Built-in screens range from 6.5 to 8 inches. More screen gives you more map -- whether it's a neighborhood close-up or a bigger picture of your whole route. A larger unit also means larger buttons, which make operating the system easier. Many carmakers are placing their screens deep in the dash to make them more visible in daylight; portable units are often hard to read in bright light. Better reliability. If you lose a satellite signal, your car system may still be able to navigate. In addition to satellites, built-in systems use gyroscopes and sensors that measure steering and speed to track your location. Even if a signal isn't reliable -- say, you're stuck in a tunnel or surrounded by tall buildings in Manhattan -- your map information is. Advertisement Less looting. The best reason to go with a built-in GPS may be this: It's difficult to steal. A thief would be hard-pressed to yank the system out without damaging it. Plus, in many cases, once a system is removed from its power source, it goes into lockdown mode and requires a code to unlock it when it's powered back up. If a crafty thief does get away with your factory-installed system, replacement is covered by your auto insurance. A portable GPS is covered by homeowners insurance, but hefty deductibles and hair-trigger cancellations usually mean filing such small claims is a bad idea. Feature presentation. Even if you're inclined to skip the built-in GPS, the features you want in a car, such as a rearview camera (mighty handy in SUVs) and an upgraded sound system, may not be available without it. For example, the Infiniti G37 touch-screen GPS system ($2,200) includes a backup cam, plus a 9.3-gigabyte hard drive for music and voice-activated controls. Regardless of the promised features of any built-in system, make sure to give it a test-drive. If itÕs not intuitive or user-friendly, you could be better off saving a lot of money with a portable.