red tend to be the original poly bush colour ,other colours different makes ,but never get cotton reel style as are harder to fit that original bushes,most come in two halves which greatlt aids fitting,they are supposed to offer greater articulation and last longer but ive had to change 1 or 2 polybushes of all different makes some few years later . but are relatively cheap and so easy to change for some one at home let alone workshop if you are fitting disco axle on front you woud want 300 tdi def kit as the difference is in front radius arm to axle bush width