I wouldn't spool it just because of the turning radius issues. I run ARB's (spools when locked) and I can't hardly turn when they're locked. The Toyota powersteering system isn't built for that kind of stress either - I am on my 3rd power steering pump.
As for the breakage question, I am of the firm belief that a front locker will PREVENT more damage than it causes. The ONLY situation where a locker will hurt you is if the tire is wedged. You can unlock the hub in that situation and be OK. All the other instances you experience off road, the most common being a tire off the ground, a locker will help prevent the shock loading that occurs when the tire comes slamming down because with an open diff, that tire is spinning 2x as fast. A locker will allow you to crawl obstacles that you would have to carry momentum through (ie - go faster) with open diffs.
