Bellypan/boat tail — I'd say generally true, with caveats.
The area under the car experiences interference drag between road and undercarriage. A rake exposes the undercarriage to the low pressure wake, a tail-dragger exposes to the front. I think a relative rake is preferable.
https://ecomodder.com/forum/showthre...rag-31649.html
https://ecomodder.com/forum/showthre...ges-13199.html
Compare the images in the first post. The problem isn't so much the gross area, but how the wheelwells (especially the fronts) are handled.