I don't know, Bara built it and didn't mention an option.

My diff doesn't make much noise at all now unless on full lock turning the car round etc. It took maybe 300 miles to settle.

I have quaife up front and all I notice is that if I slowly turn in to my drive it feels like I have put the brakes on, you can feel the tyres begin to run out of twist, it is the same doing a 4 point turn, it is easy to stall the car on full lock....so you can tell how tight they lock up front and rear...probably more so on my light 205 pug.