DarkoStoj said:
mines more like a BANG BANG BANG
Hmmmmm well IMO a Trac-Loc is sufficient for street and some/most casual track use..they typically will last 30-40K miles before a rebuild, and most of us won't drive a classic Mustang that far in a lifetime (a latemodel Mustang would be a different story). I've not heard a modern DL bang that much, but perhaps my samples were just unusually quiet.
Like all things there are tradeoffs. A DL is about indestructable but it does bring some noise. I personally would not care but as my car is 100% opentrack now you would not be able to hear the rear over the engine singing, shifter banging, etc
I have heard bad things about Powertrax, etc for racing (well, my preferred type, anyway). These are units intended first for the 4x4/offroad crowd and have migrated over to street cars to a certain extent. I know of 2 racers who tried them in opentrack cars and the unpredictable timing of the 'lock and unlock' about sent them spinning into the Armco coming out of turns

They have DLs now
I would thus avoid any diffs that are primarily for 4x4s.
I think the SoftLocker would be a good choice.
The ARB AirLocker works fine, from what Ive heard, but I don;t know why I would spend spend spend to install some air-pressure thing when I can get a locker and fugggedaboudddit.
But again I am coming at this from a "fringe" perspective to most people.