[brooksy]

It gives it that bit more forward drive. To be honest I've only run the car at worksop which is low traction with the gear diff in and it was shocking. The gear diff in my kit wasn't very good so I've put a ball diff in.
I could push it fast into corners without the loss of too much traction. Off power round the corners it couldn't have been any better.
I'm not used to that amount of grip so, as I improved every round I though I did quite well.