I have to say, I was going to do a Galaxy Tab 3 in the dash. Then I was going to do a Galaxy Tab 3 mounted to the dash, but removable. Honestly though, with the App Radio 3, that gives me all the features I would need in a tablet install and without all the headache of trying to get it done on my own.
I have an old laptop that I have considered mounting in the car, or using mp3car.com methods to install a touch screen in the dash, but the cost of that project surpasses that cost of the App Radio 3...
No matter how I look at it, the cost of the App Radio and the features it allows, makes the tablet install not worth it.