Copied from
http://www.bimmerfile.com/2016/02/22...ng-the-bmw-m2/
The standard manual gearbox is an adapted K-transmission, which is found in several BMW “Series” production vehicles and the 1M and M3 and M4. The following components were already adapted in the F80/F82 and F83:
◾Weight reduction compared with predecessor gearbox
◾Smaller size and thus lower weight
◾Improvement of the shifting comfort thanks to use of new type of carbon friction lining at the synchronization units
◾Reduction of noise level
◾Increased efficiency due to dry sump lubrication (“churning” in the oil is prevented, with specifically designed oil ducts). This made it possible to reduce heat generation to such an extent that external cooling is no longer required
So from the 1m to the current m4 the gearbox is the same