Extended bump stops are required when you fit a suspension lift, the bump stops are there to stop your coil spring becoming fully coil bound & cracking the coil spring mount off the chassis, this can happen if you land hard or hit a bump off road, when you fit taller springs to get a suspension lift, you will find you may have 1 extra coil to the spring and the bar is thicker, this means the standard bump stops will be to short and you definitely need extended bump stops. Bump stops do not restrict articulation as many think, the axle pivots on the coil spring and the bump stop then comes away from the axle, you would have to have very long bump stops to restrict articulation and then you will lose upward movement on rough terrain as you may only have 2 to 3 inches between axle and bump stop, see the last 2 pictures of my Defenders rear axle fully up in the arch, the coil spring is almost coil bound and the bump stop doesn't touch the axle. For the carrier when ordering them, it may.