I have one and it's working pretty good - Yes you can hear it if I have the window down and I'm in a parking lot making a sharp turn. As for not holding up to the power of a diesel - haven't seen that yet and trust me I beat on mine...
I really like the fact that both tires will turn at the same speed no matter what when I lay into it - I love it around corners because I just slip up a gear and mash the pedal down then hang on... The rear end of the truck just whips around the corner so of like a teenage in a old muscle car - I think Goodyear is going to put me on their christmas card list next year
The main and only complaint I have is when I turn a corner (sharp turn) under light throttle to no throttle (remember I have a manual so drive train is still directly connected to the engine) I get some bucking and it makes for an uncomfrontable situation - not hazzardous by any means just kills the ride quality - the truck sort of lunges and bucks until I either give it a little more fuel or slip the clutch a little. So for them acting like a open diff in a turn is a little bit of a stretch - maybe it would be different with an automatic because the torque converter would absorb the bucking where as a manual just transmits to the engine and with the low end torque that a diesel produces you end up with bucking...
If I had it to do over again I think I would have just installed an ARB air locker so that I could turn it OFF when I was not in need of the add'tl traction that a locker gives.
Now for traction gains - boy this thing is the cats meow. My 2wd truck can now go just about anywhere I want to go - I have been stuck in wet grass when it was a peg leg kicker but now I don't have to worry so much as long as I have some weight in the rear so that the tires can get traction away we go... No it's not as good as a 4x4 by any stretch of the means but compared to what I had before it's a world of difference. The only off roading that my truck sees is in a campground so for getting down in the mud and muck I can't give you a opinion or report on that because my truck will never see that type of duty (I hate cleaning)... But in the snow it does pretty darn well - I ended up taking the weight out of the bed to test it and I was impressed - now you have to pay attention because with a locker the rear end wants to walk when it loses traction not like it was when I had just one tire pushing - but you get used to it right quick.
I will say that since I added the locker my ET's have dropped because now I can stay in the throttle a bit more so I'm putting more usable power to the ground - before when I would nail the go pedal at 40mph all I would do is light the one tire up and if I stayed in the throttle smoke would pour from the passengers side wheel well - now with the locker I can nail the go pedal and I get a little wheel slip but then she grabs asphalt and away we go - just skitters sideways for a split second then comes the wheel hop as the springs wrap and unwrap - so the locker is going to cost me more money because now I have build some traction or ladder bars...
