If you're driving your E30 M3 hard under any circumstances, you must buy this part! when your car is under hard cornering loads (as well as sweeping turns) the engine oil starts to climb up the sides of the oil pan. This is NOT GOOD because it causes oil starvation at the oil pump. If you care about your motor, be sure to install this part (easy installation) to ensure many enjoyable cornering moments with your E30 M3.