Sat Nav - Google stylee

[T-Bag]

The maps will surely be downloaded before hand, sending the routing off to a server will make the satnav pretty useless in weak signal areas (where you could easily get lost anyway).

As for data an android phone without it is not worth having. Better off saving the cash and getting something simpler. I get "unlimited" internet with T-Mobile included. "Unlimited" mean 3GB per month according to fair useage and then they throttle it back.