Harvey I made a mistake when I ordered my 4500. Thinking I would put a Texas deer catcher front bumper on this pickup I ordered the heavy duty front springs-Big mistake. No one makes a bumper for that 4500 and have decided against it now anyway. As far as the rear suspension it is really stiff even with this bed on it(CM Manufacturing ER bed). With the trailer on it the ride is nice but still thinking about pulling a leaf out possibly. With the rear suspension that stiff it feels like the rear end walks sideways periodically causing more steering correction than normal. Getting used to it.