RacingDiffs Differential crown gear hole adapters from M14 to M12 bolts for BMW

This set of adapters for Crown ring bolts allows you to use M12 bolts with 14mm holes on the Carrier unit.

All ///M differentials have 14mm holes, therefore this adapter kit will allow you to swap the gear ratio from another differential which has M12 bolts.
The most common gear ratio swap is with E46 M3 differential. Most drivers running an N/A S54B32 engine are chasing shorter ratios, but aftermarket Gear ratio sets are very expensive. It is possible to find 3.91 gear ratio that can be used from E32 and E31, however crown gear has M12 bolt holes and E46 M3 LSD unit has holes for M14 bolts.
To solve this situation, you can install these sleeves in 14mm holes to use M12 bolts.