Bernoulli was a cool dude but I think Venturi would also claim some effect here too!
Bernoulli Effect
For horizontal fluid flow, an increase in the velocity of flow will result in a decrease in the static pressure. The equation describing this effect is known as Bernoulli's law. The most practical example of this is in the action of an airfoil. The shape of an airplane wing is such that air flowing over the top of the wing must travel faster than the air flowing under the wing, and so there is less pressure on the top than on the bottom, resulting in lift.
Venturi effect
The Venturi effect is a special case of Bernoulli's principle, in the case of fluid or air flow through a tube or pipe with a constriction in it. The fluid must speed up in the restriction, reducing its pressure and producing a partial vacuum via the Bernoulli effect. It is named after the Italian physicist Giovanni Battista Venturi.
The reduction in pressure in the constriction is a result of conservation of energy: the fluid (or gas) gains kinetic energy as it enters the constriction, and that energy is supplied by a pressure gradient force from behind. The pressure gradient reduces the pressure in the constriction, in reaction to the acceleration. Likewise, as the fluid or in the case of the GT, air under the car being forced into the constriction, leaves the constriction, it is slowed by a pressure gradient force that raises the pressure back to the ambient level
Net effect is about 250 lbs of downward force on the rear end at high speeds. So if you take off the Venturi constrictors, let me know, I have a few psychatric friends that owe me favors and I can get you a consult for free, even by email ! :willy
So what we are experiencing here is the Venturi application of the Bernoulli Principle.
If you are bottoming out entering or leaving your driveway, have some aluminum perforated trailer ramps made that you can lay down and drive the car over and avoid the scratching sound putting the GT in the garage. I have the problem with an angled drive way, I can provide an image of the trailer ramps if so desired.