The Belt Drive System is based on pulleys and belts and may shows a certain elasticity. This feature allows, for example, after a wind gust, the star to comes back on the same pixel after just 2/3 ms compared to the 2/3 sub exposures of the other mounts that can take several seconds, due to the fact that it is the motor to bring back the star in the right position. This make the difference on the final image quality.
In order to assemble the Polar Alignment kit on a M-zero standard mount is required a mount upgrade to the M-zero OBS model, to do this basically the mount base must be replaced.
This operation it must be done here at the company, so the mount must be shipped to the company.
Avalon mounts can works in the range of +50°/-20° degrees, we have users that worked fine at -20° degrees in Canada, as it is possible to read on this forum topic.