May 2013 M3W on 3rd bevel box, previous ones had oil leaks. All have been similarly noisy, 4500 miles on current one, noisiest at 60-65 mph when hot, aluminium sprocket. NVH kit fitted did not make a significant difference apart from increase the road speed at which the noise was worst. Redline shockproof oil and reducing belt tension both made a small improvement.
