I'm with Flash on this one...you guys give him a lot of **** for whatever reason, but he really knows these things backwards and forwards. Plus, he's really a nice guy in person...
Now, often I hate to say this next sentence, but..."If it worked that well, don't you think Porsche would have done it?"...they had an essentially unlimited budget for car development for the initial 944 LeMans prototype car in 1981...you know what they did for aero? big fenders and deleted pop-up lights.
And then with further development, this car "944 GTR" got essentially a really big spoiler, not a wing.
Not saying you can't get a wing to work well, but you need to be using the car in a specific way to make it worthwhile.