You can DIY for much less.
I had an old galaxy 7" tab that I put in. Cost me under $100 in parts and I already had the tablet.
I just had my tablet automatically turn on when accessory power was on. Then a few other apps could auto run. With the right apps you can have large icons that are perfect for use while driving.
My opionion, not worth $800. Yeah its cool but I don't think its honestly that useful. Doesn't excite me after the first few days. Real gauges look cooler than Torque on a screen. Most things you could do with you smartphone.
Its a PITA to load content on it or always pair it with your phone for data. But that's just me.
If you want a real nice job you can do this:
viewtopic.php?f=22&t=21888Or:
viewtopic.php?f=22&t=24309