Looking at your front end, I don't see much of the airflow going out to the sides. What I see is most of the air going down to the ground, and then the only place it has to go is under the car. I see you have some holes and a lower air entry. If you duct the outer holes to the front brakes and cut out the ribs on the lower air entry and duct it to the radiator/oil cooler (if you have one) that will reduce the air pressure at the front, and if you add a lip to the bottom of the air dam (about 3/4" [+/-]), you may then get some of the air flow to exit at the sides, but I still think that an air dam like the one in the photo in my post would be a better choice.
Looking at the front end before, you'll see that even more air was going underneath the car and hitting the front tires/filling up the wheel wells. Now there is more frontal area, but that air dam underneath has a slight V profile to it and pushes air around the front wheels in addition to not just being an open space. We added deflectors above the extended part of the dam(~3" out on either side of the body) to further support it and direct flow around the wheel wells. We plan to eventually add a splitter underneath the air dam to help trap the air there and encourage it to go around the car - as well as pull the front of the car down a bit at speed.
The holes for the factory bumper setup do have brake ducts riveted into their openings. The center, slotted area(which was blocked off completely on earlier cars) we have run blocked off, but as Marc mentions above, it may be a better idea to grab air from that high pressure area to stuff into the engine bay instead of air at the top of the grill opening. Marc has gotten a little crazy with little ducting plates behind the grill/headlights and foam stuffing in all the cracks around the grill/surrounds.
Then we have to figure out what we want to do for the rear of the car... A lip spoiler of some sort(even if it's just for fun!), and then we are likely going to do SOMETHING at the trailing edge of the roof. Maybe some spoiler that directs air down the rear windshield and straight back, or just down, or just straight back orrrrrrr some diffusers ala recent Mitsubishi EVOs...?
This, of course, excludes doing the more necessary work:
- Re-securing the seat back now that we lowered it and it's at a greater angle now
- Driving the car and seeing how the brakes work. Likely re-bleeding them with some higher temp race fluid
- Re-installing the brake ducting for the front and rear brakes
- Seeing how bad the transmission is(shot synchro?) and installing a 5th gear lockout plate
- Getting an extender for the steering wheel adapter or extending the steering shaft for better seating position
Among other misc. things.