the difference is that there isn't enough space in the factory dash in most cars (true, many cars do have this much space just kind of sitting there), including mine, for the standard form factor lcd screen. i have seen people do it, but there's a lot you have to cut out and relocate; a surprising amount, really. for the sake or not having to reconstruct the dash if i ever sell the car, the handheld seems pretty decent, and it's def cheaper.