[VGM911]

I'm not a designer or engineer. However, I do remember that the early Audi TT experienced high- speed stability problems that necessitated the installation of a rear spoiler to ensure high-speed stability by reducing lift on the rear axle.

I assume that Porsche included a rear spoiler on the Boxster (which deploys at 75 mph) to ensure high-speed stability due to lift issues. It certainly wasn't installed to improve the car's looks!

All I'm saying is that Boxster owners should be wary about installing aerodynamic devices that may destabilize the car by increasing lift at the rear. If the maker of these devices can't measurably determine the lift or downforce characteristics of these spoilers, then I (for one) will avoid them.