A bespoke composite rear wing built to fulfill the requirements of Vermont Sportcar’s VT20R rally cars.

From Subaru.com’s description of the OPEN 4wd class rally car:

The exterior of the car implements a custom Vermont SportsCar composite widebody kit, plus critical underbody protection including mud flaps and a 1/4-inch aluminum skid plate. Up top, a roof-mounted air scoop aids in cooling both occupants inside, and the stock rear wing is replaced with a larger vertically slotted wing, which greatly improves downforce to the rear of the car even as it slides sideways. No detail goes overlooked on these amazing machines.