I'd go with the mechanical LSD over the ATTS. The ATTS (Active Torque Transfer System) is a hydraulically assisted, computer operated power transfer system which compensates power to each wheel when turning. All I've heard, and it makes sense, is that it's limited in what it can do, and generally, doesn't work at ALL speeds. The weight issue is nonsense, so don't even ask about it. A mechanical LSD (Limited Slip Differential) is what you find in all rally cars, and all real sports cars. The LSD mechanically opens and and closes to transfer to the wheel experiencing less spin more power, so as opposed to an open-differential car, when one wheel spins, instead of that wheel getting all the power and continuing to spin, the LSD transfers power to the wheel which has traction (or more) and you're off. My 2 cents, by the way, congrats on getting rid of the american trash, welcome to the new world