Nice project, looks simple but is also well detailed, not an easy thing to pull off.
Seven years and +$200,000...................no wonder I never did this myself.
Years ago my wife had a Geo Metro, I thought I was going to get sucked under the side of a semi-truck tractor trailer when passing or getting passed. It was pretty scary the first few times, but a little mental preparation and a white knuckle death grip on the steering wheel helped.
Thanks everyone for posting, I've read a lot of good observations and advise in this thread.
EDIT: Sort of a Band-Aid but puts down-force right where you want it to go.
The mid-wing of a Formula-E...........Porsche just jumped in with both feet so it should get interesting.