Remember 2 important things:
as you can see on the pictures, the 335i shaft has a sliding part (to compensate engine and diff movements) that is between the bearing and the gearbox, this means that if the shaft is taken out of the car then the length can vary.
So you have to measure when the 335i shaft is still on the car, or on the car between the bearing mounting hole and the rubber guybo
The M3 shaft has no sliding articulation, the gearbox movements are absorbed by the homocynetic at the diff side
The M3 center bearing puts the shaft 10mm lower than due, very difficult to notice but it is, you will get vibrations at low speed VOT... because the guybo takes a big deflection.
2 solutions: use the 335i bearing, it fits 100% the M3 shaft, or rotate the M3 bearing with the TOP marking facing DOWN and add washers under the fixing bolts to put the axle back in line with the gearbox. no alignment needed with the diff, there is the homocynetic making the job