Add to Cart Quaife Porsche 915 (18T/43T) Quaife Atb Helical Lsd Differential, Qdf1Q - (18T/43T) $1,947.59 Quaife ATB Helical LSD differential is for a variety of models including the Porsche 915 (18T/43T). A direct replacement for the standard open differential, the Quaife ATB Helical LSD differential transforms your car’s performance. Unlike a... $1,947.59 Add to Cart