Many racers told me you need a ball diff for your mini. I didn't believe them until I decided to try one of these. I have to say, it definately give you a bit more control on how tight or lose you want your diff to be. It helps with improving handling of of your car and you need every single little bit of help you can get when you're driving a front wheel drive car straped on with a 13T brushless motor. Many ppl concerntrate on making their car lighter, but m-chassis racing is about mechanics not about electronics or car looking pretty or car being too light. Get your car's mechanics right, it won't let you down. Definately one of the must have for your mini.