Theres a lot more to it than throwing a laptop in and calling it a day. mp3car.com has some pretty good prices on the components themselves.

The PSU on the car PCs have ignition sensing wires that can order the bios to go into standby, they also have smart voltage sensing to keep brown power from damaging the internal components on the board. Even a decent brand inverter will spike to ~130 volts and drop to ~100 or so during cranking.




Theres also heat, storage, maintenance, and device compatibility.