Just trying to add some activity to the forum....
My Nano is an earlier version with the slipping belt pre-rotate pump drive.
I recently upgraded to the HD clutch option, and after some teething troubles setting it up have got it sorted and working well.
Pre-rotate is much more positive with no slipping as the rotor load increases above about 160-170rrpm.
I have posted a video of my flight yesterday on youtube- nothing spectacular, just a local round the patch- no dramas, just an enjoyable cruise.
Link here- https://www.youtube.com/watch?v=KPgixOr-Rg8
I had earlier on struck some issues with the exhaust/muffler system due to engine vibration at startup and idle.
I spent some time looking at the issue, and decided it would help to uncouple the inertial mass of the muffler from the engine to relieve any stress on the exhaust flange and joints.
I added flexible joints into the exhaust tube between the engine and mufflers, and things look and feel a lot smoother at startup/idle.
Pic below.