The SYE is a slip yoke eliminator. Kits usually do not come with these, and aren't even necessary on Rubicons, as they already have the CV style yokes. What the kits do come with is a spacer to drop your skid plate down about 2", which is supposed to compensate for the lift. Deciding on a Jeep, is like deciding on a lift, have to weigh your wants and desires in one hand, and your wallet in the other. CJ's and YJ's ride on leaf springs, where TJ's ride on coil springs. Coils ride smoother and articulate better. Do some research, decide what you want a Jeep for, and have a blast building one, or leaving it stock.CASEINATOR said:I've been reading a few strands on here and i see that alot of problems starting happening at 4 inch lifts, such as; longer drive shafts, case drops, vibrations, slip yoke eliminators, and "SYE" (which i dont know the meaning of). Do these kits cover any of these problems or do i have to tackle them myself?