[aerohead]

Track cars are primarily concerned with cornering.Low drag might help you on the Mulsanne Straight at LeMans,but you need downforce in the curves.
I would never look to track cars for insight into low drag for passenger cars.
For low drag,the wheels and tires must be integrated into the body.You can use fairings to do it,or active suspension to bring them into the body at speed,or some of both.