Aluminum rear uprights
By using the aluminum uprights you eliminate the wobbling of the axle. Try moving your rear tires left and right by hand and you'll see what I mean but with the upgrade it is almost eliminated and would also prolong your 950 bearings. Also it elimiminated the gritty feeling when the axles are turned. The upgrades are very smooth and perfectly aligns the bearings and the axles. Two thumbs up!