Spacers: Polyureathane vs. Aluminum

Lift height being equal, neither one allows for more travel. In the past, the poly spacers have been known to crack and break down. Its been a LONG time since I have heard of any problems with them. Aluminum can break, and its been a LONG time since I have heard of one breaking. The poly spacers are usually consisting of a Preload spacer combined with a Top load spacer. That distributes the lift between spring compression and lengthening the strut. This gives the best compromise between ride, and lift for a spacer. Poly spacers alos offer some sound deadaning quality, because of the material used to make them. Aluminum spacers are usually 1 peice, and are either a top load spacer OR a preload spacer. Top load spacers dont affect the ride, but can destroy the ball joints in the upper control arm. Preload spacers can make the ride very stiff, and when combined with stock shocks wich are not valved for the increased spring rate which is given by the preloading of the spring, the ride is compromised further.