There Are A Plethora of navigation products on the market - and we're not even talking about all the portables produced by companies that you thought had nothing to do with navigation. If you're looking for a quick cost-effective option, you can certainly buy a PND (personal navigation device) as an adequate solution. But nothing in this world is free. There's a reason why you pay only a few hundred dollars for something that you have to stick onto your windshield. Never mind that attaching any device to your car's window is aesthetically abominable (and illegal in some states). The real problem here is that portables just don't measure up in terms of performance. Satellite acquisitioning times on a portable can take forever. For general consumers, buying a consumer electronics product is a lot less scary than a head unit that requires going to a specialty shop. Certainly we recommend getting products installed professionally (if for nothing else than the warranty), but people shouldn't feel inhibited by any fear related to installing in-dash navigation units.
Installing a navigation unit is far less complicated than it appears on the surface. Any patient DIYer brandishing the proper install tools should be capable of connecting one. The word "patient" is employed because you won't find the extra connections needed to complete your installation at the factory radio wire harness - you might have to dig through a few additional harnesses to find the correct wires. These extra connections generally consist of a parking brake, backup light and speed pulse wires. The latter two connections help a nav system perform accurately, while the first ensures certain functions are performed safely (at a stop) without distraction, thus keeping the manufacturer's legal team out of court. Fortunately for the DIYer, most manufacturers keep a thorough database of vehicle wire color combinations and a location to find them in your specific vehicle, making the hunt a little less painful.
Besides these three wires, a navigation system requires a GPS antenna. While it's best to locate the antenna in an uninhibited area outside the vehicle, most will work well behind the windshield, atop the dash.
The question of bypassing the safety measures so that all of the navigation functions are available while the vehicle is in motion is a thorny issue, one that manufacturers have thought seriously about. Can it be done? The answer to that is yes and no. Over the years, navigation systems have become more sophisticated and now rely heavily on the speed pulse wire and GPS to indicate movement, shutting off key functions of the nav when sensed. So what about the "yes" portion of this answer? Glad you asked. By bypassing, or grounding the parking brake wire, newer car-specific navigation units don't suspend these functions until the vehicle reaches a certain speed (typically limited to under 5 mph) or the vehicle moves over a certain distance - a foolproof design that keeps lawyers happy. Ultimately, bypassing the safety guard is really a worthless measure.
The following pages are reviews of navigation products from the major aftermarket manufacturers, some DVD-based nav units and others that have hard drives for storage of map data. Rather than simply focusing on the navigation element of these head units, we looked at the overall package with a focus on how well the products worked for navigation. While there are significant differences between the various units (DVD vs. HDD, differences in menu setups, ease of use, etc.), we feel that consumers and enthusiasts will want to consider the products as a whole. Considering the healthy price tags, buyers should look at everything they're getting before buying.
 Clarion MAX675VD/NAX970HD...  Clarion MAX675VD/NAX970HD | 
JVC KD-NX5000 | 
Panasonic CN-NVD905U |
Eclipse AVN 6610 | 
Pioneer AVIC-D3 | 
Kenwood DNX7100 |