I am looking for software (windows) tools that allow logging of both OBD and GPS data, such as speed, mileage, and location. I would prefer some software development kit (API, prefer. a classic winapi32 DLL) Any ideas where to look. What OBD2 hardware/interface is recommended these days? (I have a VW Caravelle that this will be used in to start with..). Also, how is mileage calculated from OBD data?