The standard D4 coil in the LV3 is a 600/1200 roundwire coil, the D2 coil is a 1000/2000 8 layer flat wound SPL coil. They are compleatly diffrent, if it was just the same coil but only a diffrent imp. change than they would be the same price. With the D2 coil you get more power handeling and overall more output from the subwoofer