Get the spicer heavy duty. As stated above, forget the aftermarket ones with the zirk fittings. The problem with most u-joints arise from water displacing the grease in the cups. This happens during high speed rotation in a wet environment (rain). The spinning joint acts as a centrifuge. Since water is heavier than grease, the water goes to the end of the cup and grease is displaced out toward the center of the joint. Spicer joints have a better seal that discourages water from entering the cup. I am not saying that Spicer is the only one that has the better seal, but I know that they are one that does. Besides, while redoing the clutch on my 92k mile original joint LT4, I found the joints (GM uses spicer) to be OK. I did replace however since I was in there.