And yes I do, took the car for mot earlier and the tester asked if the car had limited slip diff, I answered yes and then he informed me that it would not be going on the brake test rollers in case the diff gets damaged. He then accelerates behind the garage and slams the brakes on a few times and gets out holding a little electronic box with a digital display on it. Apparently he placed it on the floor of the car and its internal sensors calculated how quickly the car had come to a halt. How cool is that.