Front Lip/diffuser im toying with
 

Pics speak for themselves, from mockup to mounting. retained the factory s4 lower lip for added support. Its made out of 1/8" PVC Plastic sheeting. If i decide i like it i will probably pop for the $140 a sheet 3/8 or 5/16th stuff. It still needs to be sanded on the front edge to be evened out, this was just a quick cut with a jigsaw to see if i even liked it.

If yer gonna say "rice" then dont post. A friend watched it from his car while i was driving at it does bend flat when driving so im guessing its having some effect to divert air into the mouth and under the car.

If i keep it, ill probably paint it black since thats the color the rear diffuser is going to be when it gets installed. I figure its slightly different than the same ole shit I see. I just havent had the time to sit on mcmaster carrs website to find some adjusting rods for it.

And now the link to the album: http://imgur.com/a/zCrk2#RSgpM

What do you mean "it does bend flat"?

its hard to tell from the pics but due to the way its mounted, it has a slight upward angle (f looking at it from a side profile its not quite flat coming off the bumper. hard to explain

i like your car without it. I think your car is too clean right now.

It probably won't make much difference in aerodynamics without going more extreme, flat panel under the front of the car etc.

Just get a lip and you will be rockin

the flat panel is already underneath ;) but im keeping that project to myself.

Ah little thicker and I think it'll look great... It just seems right now like it's about to break off

I'm not keen on that lip, think it spoils your clean look. Just my opinion.

I would make it one piece out of dry carbon, you can buy full sheets of it for aviation use, and it would add next to no weight, and look alot better in my opinion. The hard part is drilling the holes because carbon fiber is very brittle, just do some google-ing on how to cut/ drill graphite, and you'll be set. But all in all its not bad, its not the best look for a stock S4 bumper, Maybe adding a lip and mounting it under the lip would look better. Also if you want to go for a race look canards can do alot too, but make sure you have the rest of the car built up first, adding aero to relatively stock car is going to get you a lot of flack from purists.