Welded centerdiff is far stronger than the stock diff. They are not that bad daily when your tires are of equal size. but if you are making any power and have wheelspin, your tires do not stay the same size for very long. then it becomes quite annoying as the drivtrain is fighting itself as tires try to travel different speeds.

the stock two spidediff is quite weak. and it doesn't withstand wheelspin. when the rf tire starts to spin it tears up the washer on the outer gear inside the diff. the diff gears are now looser than they are suppossed to be which make the diff even weaker. the grinding washer also sends fine particles of metal into the oil which makes the tranny wear out faster and shift like crap.

the only real way to mod the cd IMHO is to go 4-spider with the torrington bearing side gear mod. this eliminates the weak side washer, so you can spin away trouble free.