JC,

Luckily I have a good racecar aero guy that is helping me concept and design. I will fine tune at A2, i.e. Diffuser plate sizes and shapes, wicker bills, etc. I consider it cheap insurance as apposed to flipping the car at Bonneville.

The stock rear spoiler has already been tested on this body style by someone else and the numbers are good for what I'm after. A long, flat deck spoiler would create equal down force with less drag, but not the look I'm after. I'll sacrifice drag for cosmetics, but not cosmetics for stability.