My impression is that massive add-ons increase drag but shaping the underbody is 'free' down-force. kach22i says there're radiators, but I don't see much intake opening and only one exhaust.
The unaerodynamic thread is for things like this:
http://justacarguy.blogspot.com/2016/10/i-think-they-designed-this-soapbaox.html