The more acceleration or deceleration applied to a pair of tires, the less traction is available for lateral acceleration. They used to call this the "circle of traction" theory. The fronts do the lion's share of braking and the rears do all of the acceleration (on an E30). It is difficult to eliminate braking forces going into a corner on a road course and still be fast.Braking detracts from the lateral acceleration capability.The extra weight increases the braking demand.There is a loss of lateral acceleration potential in a pair of tires as weight is transferred between them.A skidpad is close to a steady state situation where the speed is increased very slowly. They are a big help in springing the car in relation to front/rear weight and getting the desired amount of body roll .