lofi said:Worth a chat with centre gravity. When I spoke to them about high speed stability (my turbo seemed to be lacking - and we're talking normal speeds not 215) they immediately pointed to the rake of the car. These car tend to sag down at the rear. The change they made to get closer to factory rake was small but the difference it made to high speed stability was huge.
Spot-on; a car is effectively wing-shaped (especially a 911) and if the rear sags, it increases the angle-of-attack of that "wing", so you get more lift all speeds. So stance is actually a huge aerodynamic factor, as well as all the air dams/splitters and spoilers rightly mentioned elsewhere.
Aerodynamic effects increase as square-laws usually, so pushing a car beyond its design speed can rapidly become very interesting!