Genuine BMW M Performance Limited Slip Differential. Fit F20, F21, F22, F23 M135i M140i M235i M240i. Your chassis number can be found on your V5/registration document next to VIN/Chassis/Frame No. And it will start with WBA, WBS, WAP, WBY or WMW. It can also be found in the bottom corner of your windscreen on
