We designed and built a number of other mods, like the shoulder belt attachments and the battery box, which don't make the car drive better but make it more usable.
The battery box, which places the battery under a small hatch in the trunk floor, allows us to have full use of the trunk space, something not normally available in FFR cars with IRS because FFR says to put the battery in the trunk. This was mostly my concept and design, with input from Nate, and Nate did the fabrication.
The shoulder belt attachments are very simple, made of angle iron and muffler U-bolts, and allow us to have a shoulder belt installation that's legal for COMSCC time trials and other competitive events. Again, this was my idea, based on a concept illustrated on the FFR Web site, and fabricated by Nate. FFR's site has a photo of a similar device, machined from aluminum billet with a stainless steel bar, which I believe was made by Jack Rosen. I figured out a way to do this with parts and tools to which we had ready access. It's heavier and not as pretty as Jack's solution, but it works.
See the Build section for photos.
After a few events on our Yokohama AVS Sport street tires, we realized that everyone else in clubs like COMSCC and EMRA is using DOT-legal race tires. We bought a new set of Cobra R-style wheels from Performance Wheel Outlet and a set of shaved and heat-cycled Kumho Victoracer race tires from the Tire Rack.
These new tires are not only several seconds faster, but they are much more forgiving than the Yokohamas, making it easier to get near the car's limits and reducing the chances of spinning.