During a visit to Blitz Helicopters new web site I found a Main Shaft Bearing Enhancement, which was duly ordered.
True to form it arrived the following morning.
The kit supplied places a third bearing on the main shaft, as this is a retro fit additional holes are required in the main frame. To achieve this, a carbon fibre template is supplied, and as you are required to drill holes they even supplied the drill bit.
A simple enhancement, well worth a look.