yes, gps is embedded, BUT one of the problems I've found is that andriod is kind of funny in that when the gps app looses focus it doesn't continue to track gps to save power, so when you switch back to the gps app it again has to get a lock to "find" itself. this has been a pretty major hassle when trying to go to a gps app while moving on the highway, it takes a bit of time to get a lock again. how it is oriented in the dash and how much it is being blocked by the vehicle can also play a part in this. there are 2 solutions.
one is to get a bluetooth gps antenna, this will get a lock and then keep it all the while it's powered up regardles of what app is in focus on the tablet, so when you go back to a gps program the gps antenna is already locked and it's much more seemless. the second way I've found is even better, what you do is start with a 3g/4g tablet, even without service... the 3g/4g device still has a cellular radio onboard and it still connects to the network even without service. now of course without service you can't use this connection for data but it still does at least connect to the network. where the benefit of this comes into play is that a tablet like this can use the cellular network for additional location services, so now your getting location data from both the gps and the network, even when gps looses focus the network location keeps location, so now returning to gps it gets a lock in a few seconds because it already knows approximate location as it starts.
I've been through a few tablets to iron out all these things, first one had no on board 3g/4g radio, but you can go in knowing this and make your life a little easier. second thing I'd tell you is don't buy a cheapo tablet. one of the things you are paying for with a much better tablet is a much better screen and in the car this is critical, it's pointless to save $100 but wind up with a screen that you can't see during the day because of glare and dim lcd.
as far as getting the sound into your car, that's easy. you just need an aux input, then the audio from the tablet inputs to the aux input. in this way you can control volume with the steering wheel control and you can still switch to fm with your stock head unit if the need arises.
a data connection in the car is going to really help for full functionality. google nav uses a data connection and won't work without a data connection. there are other gps programs that don't require a data connection though if you really can't have one. I use my phone for data, teathered to the tablet wirelessly. this would be what I'd recommend. it's awesome for streaming music from pandora, watching netflix while waiting for someone, web browsing, the list goes on and on. you can do without a data connection but for the real "live" dash feel data is a must to me, guess just because I'm used to having it though. you could of course just load up mp3's locally and get a nav program that doesn't require data and do without it I guess, but to me it's well woth the extra $30 a month or whatever it is...
