I'd like to know if the cars (Skip Barber) in dev mode have reflective paint coating or just specular? I don't know If I'm not setting up the car reflection map properly in the GMT exporter, or they just don't reflect by design.
Have you checked the checkbox 'Live Mapper' in the screen of the cube map and have you entered 'REFMAP0' into the field 'Reflection Mapper', that is right beside of the 2 fields where you set the materials transparency? The shader should be 'Car body paint +damage + rain'.
