My son and I purcased our 91 YJ. It already had a 4" lift, 33" tires and wheels. Right after we got it we lost the drive shaft. So we removed the slip joint and replaced it with the yoke type with a new drive shaft. Then the yoke strapbolts broke and lost the new drive shaft. With great help from this forum we replaced the straps with the U bolt type.
Our next project was replacing the ring gear and pinion frt and rear with 4:11 ratio with posi-lock in the rear.
I believe we are set up as we need to be now. Jeep runs great and goes up and down trails great.
We may need to cutout the fenders but haven't completly decided yet.
I might mention if you purchase something that has already been lifted make sure to check the spring bolts for proper torque. Ours were very loose and was probably some of the cause for looseing the drive shaft.