The Kenwood KVT-516 is a nice unit, but it is only IPod ready, BlueTooth ready, and Navigation ready. Meaning if you want to use it with an IPod, Bluetooth phone and have navigation capabilities you would have to add on the following modules:
Kenwood KCA-iP301V IPod Adapter 29.99
Kenwood KCA-BT300 Bluetooth Adapter 149.99
Kenwood KNA-G610 Navigation Adapter 599.99
Then, if you want traffic on your GPS, you will have to buy the Kenwood KNA-NT100 at an additional 149.99.
For a total price with head unit of 1579.95. That seems pretty extreme to me.
I bought my Garmin 1490T Refurbished for 180.00 which includes lifetime traffic, bluetooth, and a 5" screen. It has all of the latest features. My head unit is an Alpine iDA-X100M which comes with an IPod connection that I paid 200.00 for. So, for a total of $380, I can do everything the the Kenwood unit can do with the exception of DVD playback for 1,200 less, and still have quality equipment. To me, I do not care about DVD playback in the Crossfire as I am too busy watching the tach and the road.

On my Honda Odyssey, I do have a double din unit, and I love the DVD playback on it.
To each their own, but I would rather get a nice head unit at a decent price and purchase a semi-disposable GPS every few years. I would hate to spend 599.99 on a navigation unit and it become obsolete in a couple of years.
I have a high end Double Din head unit in my daily driver. It is an Alpine IVA-W505, and I opted to go with a standalone GPS instead of purchasing a navigation module for it.
So, I would disagree with you. It is not bad advice for what he is asking for. People are trying to explain to him the benefits of purchasing a stand alone GPS versus an integrated one. Everyone has their own opinion and budget, but I for one would not spend $1,600 for an in dash head unit with bluetooth and GPS.