Can someone please steer me in the right direction, I have 08 tahoe with non-ride sus. with 2 inch Mcg. spindles upfront and 3/4 belltech springs in rear set on 3 inchs, with shock extenders, my ride is pretty decent up front but the rear is harsh, I have read about the blistien shock but I dont know which model or part # I need, could someone please shed some light on which ones i need.Thanks