well, you have options. what do you want it to do for you? what all driving conditions will it be subject to? also, and very important, whats the budget?
as far as installing, all but the ARB are super easy. especially if your not changing gears.
the "lunch box" locker is the cheapest and easiest. unless you are ok with a spool/fozzy locker. the spartan/lock right replaces the guts of the open diff, and work well. but they can be "glitchy" on the road. sometimes they will load/unload and sort of feel like the whole car is trying to change lanes. but, all auto lockers do this.
a spool is a solid chunk holding the ring and both shafts tight. for zuks, this also replaces the guts.
a fozzy lock is a welded set of guts from an open diff, that are esentially a spool as it is always locked. but there is some movement between the gears which is better for street manners. its also the cheapest, barring you have a welder and know how to use it.
all of them have on road drawbacks. all work great off road. but, the auto lockers can and will break at some point.
the ARB is the best option, but it is $$$$.
shop here for best prices
www.lowrangeoffroad.com
spool-
http://www.lowrangeoffroad.com/inde...rai-26-spline-mini-spool-locker-141043-3.html
spartan locker-
http://www.lowrangeoffroad.com/inde...uzuki-samurai-locker-1985-1995-sl-suzsam.html
lock right-
http://www.lowrangeoffroad.com/inde...ifferentials/powertrax-lockright-lockers.html
ARB-
http://www.lowrangeoffroad.com/index.php/suzuki/samurai/differentials/arb-air-locker.html
this is the best zuk site for info and help.
www.zukikrawlers.com im zukrider on there as well.
id also be willing to help through any of it, though i have no ARB experience.
good luck with the choice!
. I'm currently running stock tires and plan to for some time due to petrol prices. I'm looking for overall better traction out of the vehicle and I've heard none stop that it is one of the best investments for offroad capability. I'm not looking to do rock crawling or anything like that, mostly forestry roads, and the occasional "sleeper" attack on a jeep.