Nice write up. Thanks.
How are you able to use the front lip if it has to be OEM?
Also, here are some brake duct supplies for cheap. http://www.m3post.com/forums/showthread.php?t=374717
Just follow Junior M3's write up in the DIY section.
Willow should not cook the brakes nearly as much as Cali-Speedway, which is pretty hard on brakes. Just don't go off at Willow... you'll be in the rocks or a ditch. And bring a tent for Willow in July. It's HOTTTT.