HOME // FUN & FORUM TV Commercial & PROMOTION VIDEO Information. There are many rumors to which is better out there but Tein, the suspension specialists, will put an end to all those rumors! There seems to be something still going on with sought-after EDFC ACTIVE... EDFC for In-Car Damping Force Adjustment. Let us bring you the story behind the development of its new model. An introduction, covering numerous important points, to assist you when installing TEIN products.