If your running the spacer in the shocks or the drop pistion in the shocksb take them out. My 2 wd seem to do great on a large outdoor 1/5 SCALE TRACK and it very blown out. I have the sways on the 4x4 I use the 1.5 I the rear and the 1.8 I the front. I'm thing of trying a 1.5 in the rear my self but I have to get the sway for it. Mine does do great without. I only run the stock class in the 2 wd so I'm not sure if that matter but it did help the 4x4 out a lot