SEMA 2010: Honda Unveils Mugen CR-Z, Hybrid R Concept

Contrary to popular belief, a rear stabilizer isn't there to provide downforce for launch traction, but rear suspension stability at speed and reduce boundary layer seperation. Even on rear wheel drive cars, the fact remains that at low speed where the car needs addtional traction, there's no airspeed to generate any additional downforce and therefore grip. The stabilizer functions to add a load to the suspension so unduluations encountered which are harmonic with the suspension do not upset the suspension. Also, because of the shape of most cars, a sharp rake in the back causes what is known as boundary layer seperation which the laminar flow boundary at the very close surface of the car (millimteres in thickness) seperates and causes great pressure drag, slowing the car. Although, the hatchback design doesn't benefit from this function, it still benefits from the suspension stability.

If you look at open wheel cars like Formula 1, the vast majority of aerodynamic downforce is contributed by the undercarriage ground effects despite stiff regulations on such appendeges and penalties for missing requirements. Lately, constructors continue to obtain more and more downforce per given airspeed despite being regulated so greatly. In the interest of sporting competition and overtaking, such regulations are maintained, but were cars to be less regulated, you'd see substantially greater levels of downforce, grip and cornering capabilities approaching that of low speed planes.