This is the optional Yokomo BD8 2018 Rear Toe Control System. The RTC essentially uses front hubs, knuckles and steering turnbuckles to provide a rear end with adjustable toe. Need more rear toe-in? Loosen the turnbuckle to increase toe angle. Too much rear toe-in? Tighten that turnbuckle for less rear toe. Super simple.
It is important to note: Because this system does not use a fixed rear toe angle, you will need to manually check the angle to ensure the left and right side are identical. This can be achieved by ensuring both turnbuckles are equal length, or use a camber gauge as the vehicle stands vertical on your bench.