Leonardo have been very cagey about it, but looking at the photos, the differences you can notice are:
1. New nose profile, which looks very similar to the AW169, this hints at a charge from Honeywell to Collins avionics as the Collins system uses the more traditional ARINC box architecture rather than the Honeywell MAU and hence takes up more space, hence the need for the new nose.
2. New engine inlet, which could be a new engine such as the PT6C-67E or a PW100 series varient.
3. New tailboom as shown by the flow visualisation strings.
Be interesting to see what they end up with.