I'm trying to make my 3rd. Gen WiFi only model compatible with an app called iOnRoad. The only trouble is, when I try to download the app it states "This app is incompatible with this iPad" "This app requires GPS". I'm concerned that I won'tbe able to download the app even after I purchase an external GPS. If you have a WiFi only model with an external GPS could you please try downloading GPS by TeleNav and post the results? I get the same incompatibility message when I tryto download that app as well.