Dont think its going to be possible with a spoiler. It would take a huge defuser on the bottom of the car like a supercar, a spoiler on the top so long it would look like a surfboard.
Cheapest solution is to keep a bottle of windex and a microfiber cloth in the almost useless hatch compartments.
Cheapest solution is to keep a bottle of windex and a microfiber cloth in the almost useless hatch compartments.