Not a bad idea! The wing needs to be that height to function properly. I know someone is thinking it, so I'm gonna clear up a few things.
FWD's don't need them, there pointless
First, what is the number one problem that almost every fwd suffers from? Understeer. Under acceleration, weight transfers to the the rear, causing the front to lift. How do you fix this? Higher rear spring rate compared to front. So say your coils come from the factory
With 7k front and 5k rear. An ideal spring rate would actually be closer to 7ront and 10k rear because less transfer to the rear equals more grip at the front. The reason coilover manufactures don't do this is due to rear end stability, or lack there of. Anything above 60 is just terrifying. Well the cure is a wing. You get to keep that high rear spring rate for low speed corners and you gain rear end stability by the added weight created by the rear down force created by the wing. That's it.
They don't do anything but slow you down-
Actually depending on the angle of attack, you can change the drag created by the wing. Some can even eliminate drag all together.
