im going to have to be the first to say front
what are you driving? if it is a newer jeep, i feel a lot more comfortable driving on a locked dana 30 front than a dana 35 rear
if not, that of course doesnt apply
if this is your daily driver, i would especially recommend the front first, for the driving manners, a rear one will have a tendency to bind up and unload on the highway, not such a great experience with lockrights
i have a lockright in my front 30 and couldnt be happier that i chose to do it first, it is 100% un-noticable on the street, the only time i know it is there is in very tight parking lot turns, and then i mostly hear it, just barely feel it
also, the performance is great offroad, i cant think of one situation that ive been in that having only a rear locker and an open front would worked better than what ive got
adam