Re: Welded diffs!!
All three things you were told are false.
A welded rear diff drives very, very nicely on the road. On the highway, you would swear it's an open diff. Only around town in tight turning maneuvers can you tell that you're "dragging" the inside rear tire as it spins faster than the ground moving beneath it.
There is no hopping sensation at all. It drives as smooth as silk. An automatic locker (Lock Right, EZ Locker) can create a "hopping" or lurching mid-turn if you are abrupt with getting on the gas without smoothly slipping the clutch. This causes a rapid lock-unlock-lock-unlock cycling of the locker from the natural "slop" in the driveline. It can only be stopped by turning straight or rolling to a stop. But a welded diff will never do that.
And lastly, I don't know what your friend meant by "tearing the hell out of the front end" but it doesn't do anything of the sort. The only thing I can think of that he meant was that the tires get worn out faster. The only other negative factor with a welded rear diff is the slight reduction in turning radius. Other than that, I absolutely loved my welded rear diff. The reason I went back to a locker is because my tires were wearing out too quickly due to my Samurai being my daily driver. I still wish I had the welded diff, but I can't afford to wear out these expensive Swampers.
One thing that I will highly recommend against is a welded front diff. You will never be able to get your Samurai to turn when the hubs are locked in. You'll also be just asking to break the Birfield joints. But if your Samurai doesn't see a whole lot of in-town driving (you stick to the highways and trails) then by all means, go for a welded diff! If I ever get another vehicle to use as a daily driver, I'm putting a welded rear diff back into my Samurai.
-- Geoff Beasley