Van Steve Neu zelf:
For most people it really does not mater if a motor is a "Y" or "D" as long as they have a motor Kv that works for the application. Y and D refer to how the phase wires are connected together. The one item about the D vs Y is that Y type motors can accept some advance when you need a little more RPM or power from a setup. D type motors don't get any power boost and actually will just make more heat when run with advanced settings.
Steve