if you think you might install larger tires in the future, like 35's, i might recommend that you hold off on lockers until you do that so that you can regear at the same time. lockers will replace your carriers and really, one of the biggest cost to installing lockers is the labor. needless to say, you might as well do that at the same time. down here in southern california, you can get gears installed for about $1000 USD at off road evolution. i would highly recommend something like an ARB locker as they are selectable and each of those cost about $800. you will need to get a compressor to run them and that will set you back about $200.