The 3″ brake duct is fed from the NACA duct to the Singular Motorsports bracket that actually cools the rotor.
The rear brakes use a Stoptech STR21 2-piston Trophy caliper on a V8 Roadsters custom alloy hat and scalloped rotor friction ring. All of the brake lines are Stoptech stainless steel and brake proportioning is handled by a Wilwood Prop Valve.
The rear wheels and tires are identical to the front 949 racing parts.
The cage was built by Blackbird Fabworx out of DOM tubing and fully dimple die plated to the unibody for stiffness. The cage is a 3/4 cage with the rear half being full NASA spec with added door bars but without the upper forward halo. This is like something found in a Factory Fiver racer but better.
A Cobra Evolution seat sits on Blackbird Fabworx custom seat mounts to get the seat as low and as far rearward as possible. Sparco HANS compatible 6-point belts are used to keep the driver in place. The trans tunnel has been modified to get the seat more rearward and closer to the center of the car as well.
You can see the triangulation of the rear part of the cage here. The hardtop has been lightened with a lexan rear window and a dry carbon skin.
The door bars are quite strong and greatly increase chassis rigidity. They also have receptacles for the removable jacking points.