Ok, what you need is epic mount (if not you get just 60%) and XYZ.
not sure if this is old or something, but I just found it out.
you mount up, jump up with xyz and remove mount in the air, then you get disconnected, and when u log in you have 100% more speed
you loose the speed when you stealth, get slowed, get feared. as far as I have seen so far.