[BevanWright]

Thanks guys, some useful ideas.

I have thought about blanking off most of the front opening, as my car runs reasonably cool, I still need the oval holes, as these feed cool air to the brakes via a tube on each side down to the brake caliper and hub.

I vaguely remember holes in the back guards of some Shelby race cars, I think the ones with cut back doors (the model escapes me at the moment), the holes were a kind of quarter moon shape.

I know a small lip on the boot would help with cornering, but I am after bulk downforce for acceleration from reasonably low speeds as well.

I will take some photos of the cover for you. Basically it is shaped to sit on top of the body where your window normally runs from side to side, along the top of the door, and along the top of the area behind the seats. The panel is reasonably flat with the exception of a hump around the back guard, and a curve up from the door to the height of the bonnet. In my case the panel is painted with the blue and the orange stripe. The panel is held on by dzeus fasterners (my car is a bit like 'The Turd' in respect that the front and back lift off), so everything is able to be removed quickly.