I recently received (to the UK) a customised GT race light diff and DCT 3.62 final drive from Florian and all I can say is WOW, the difference versus stock is huge! The car is so much more fun and grips and grips and grips.
For anyone thinking about it, it's a spectacular upgrade and really changes the handling characteristics of the car for the better
the level of wet grip is also impressive and it will drift with ease if asked to, it's very predictable and makes for a very fun car.