I have been interested in Tom Frederico's new sway bars and springs. Since the stock Impala springs and most of the after market offerings up to this time have been linear in rate what is the advantage or disadvantage of a progressive rate. My assumption would be that the lower inital rate would make for a better ride on the street and that the higher final rate would help on the track. However, there could be more body roll and different reactions to mid corner bumps. For example what happens mid corner when the car is heeled over and you hit a bump hard enough to double the spring rate momentarily. Seems like that could be unsettling to say the least. Any suspension engineers out there?