I have an aussie up front in mine.....Don't know about the Lock rite, but you cannot hear the aussie at all. I ran a little heavier gear oil...85w to 140w and had several friends listen all day trying to hear it. They were pretty suprised as was I.
I don't think you will go wrong with either, but I do know the aussie is much smoother and quieter than a powertrax I have in my suburban.
That's my .02 cents.
Steve