coilovers. The back ones are always much softer than the front. In fact the more expensive (read: better) the shock the softer and longer throw it is. A deeper squat and slower rebound keeps the back end lower through hard launches. This gives better weight transfer, and keeps more weight over the rear wheels longer which translates to better traction. I just invested in a set of HKS 4Way drag dampers for the rear..... HKS *normally* sells these for $2500 for the rear set only. They are very soft with full adjustability of the rebound.