Engineered by algorithm. Validated in CFD.

The GR Corolla is a rally car for the road: all-wheel drive, a turbo three-cylinder, and a chassis built to be driven hard. Its aero tells a different story. At 112 mph (180 km/h), the stock car makes nearly 470 N (106 lbs) of lift, meaning air pushing the car up, off the road. Most of it is at the rear, which is the last thing you want when you’re committed to a fast corner.

THE KIT

Every part in the kit was refined with the same computer optimization methods used in Formula 1, then tested together in a full-car airflow simulation (CFD). The result: nearly 470 N of lift becomes over 460 N (103 lbs) of downforce, a swing of more than 900 N (about 200 lbs) pressing the car into the road instead of lifting it. Front downforce more than triples, so the car turns in with real bite, and rear lift drops by 60 percent, so the back stays planted in fast corners where the stock car goes light. Figures are for the complete kit, not this part on its own.

DESIGN

The Carbon Fiber Rear Diffuser is three pieces that fit over the factory diffuser instead of replacing it: a center piece flanked by two side fins.

FITMENT AND INSTALLATION

The center piece attaches with factory clips and is secured with 3M VHB tape. For the first 24 hours, avoid washing the car and park it in the shade or a garage when you can. The side fins attach with factory clips and can also be secured with 3M VHB tape. All hardware is included, and installation takes about an hour or less. The diffuser also fits cars with aftermarket exhausts. Exhaust covers are not included.