In other words, there is no reason to do this. BTW, you forgot the excessive cost of repair if it breaks, and the week it'll be in the shop if they have to pull the dash apart.
Whereas if you buy a separate unit, you can either mail it into the company and drive your care freely until the replacement arrives, or if it's out of warranty, toss it and buy a new whenever you please.
Meanwhile, if you have an in-dash unit break, and it's not worth fixing, or you don't have time to take the car into the shop, you have a ugly non-functioning unit in the front of your car for everyone to see.
When I read the reviews on CNET, I obviously see a lot of emphasis on technology and gadgets. However, while I can appreciate this (that's why I'm here) I don't understand why, as a consumer, I should ever choose to purchase an in-dash navigation system in a new car.
- They are far more expensive than aftermarket units (usually seem to be about $2k vs. some nice portable units for $200).
- You can't take them with you (My wife and I each have cars... in fact, I also have two classic cars). With a portable unit I can use it in any of my vehicles. Also, I really want nav when I'm in a strange city, not when I'm driving my daily commute. The portable units are now little bigger than a cell phone so I can take them with me when I travel and rent a car.
- In-dash GPS seems to often complicate the usability of other features like the stereo and climate controls which all use the same display or touch screen. This is a big negative to me. I don't want to scroll through two or three menus just to save a radio station.
- Resale values for cars put little value on GPS... look at some late-model cars, for example. KBB puts as little as a $200 value addition for GPS.
So, other than the fact that they often look cool, why tie myself to one technology during the 3-4 years I'll likely drive my new car?