I have Lock Rights in both axles of my '95 YJ, with stock shafts and 33" tire, 4.88 gears. I've had them in there for about 10 years in the rear and 7 in the front. I wore the rear one out after 9 years but so far (knock, knock) I haven't broken anything. Yes locked differentials affect the way your Jeep drives, but a reasonably competent driver will adjust in about 5 minutes. You just need to drive your Jeep with a little restraint. More finesse, less brute force. If you're going to install Detroits in your diffs be sure to regear for your tire size. Driving locked diffs with stock gears and larger tires will put much more stress on your parts making breakage more likely. It also makes driving slow more difficult and the ability to go slow is paramount when in the rough stuff. If you can afford alloy shafts then by all means slide 'em in there especially if you don't know the history of your Jeep.
Wheezer