[RC-Monster Mike]

18 cells will require a stiff spring. Dual rate springs should work well for you, as long as they are the right spring rates (pretty stiff for your set-up). If you still have the stock shocks, you will blow them pretty quick. You can use the same springs for different types of driving (not necessarily ideal, but it sure beats changing springs all the time). You can adjust preload and shock angles for different driving conditions. For heavy jumping, you will need a heavy shock oil, though.