walawala

hi......don't know the oem differential open diff or vlsd.....not the axels.i means the pumpkin.i can‘t install the cusco lsd into the oem pumpkin.do i need to change a pumpkin?

Hi guys. i'm totally a noob. i've purchase a cusco lsd for my 2006 350z 6mt.the part number is LSD 251 L15. but it's not compatible.i don't know why. my vin is:JN1AZ34E56M100018 and the rear differential pumpkin part number is:383110c000. please check the pic.the left is cusco,right is oem part. now i was plan to purchase quaife lsd. but don't know which is the right part.i don't want take the wrong part again. and what is the difference between QDF11L&QDF13L.i've compare the cusco lsd. they have the same dimensional. looks like the QDF10L will fit with my oem pumpkin. is there anyone can help me. thks