Igloo
Not a mod
I'm fairly sure Griffen is not faster than Deledio. Do you have a measure of their speed?
Watching over their careers, it's pretty clear he is. Deledio undoubtedly has better endurance, but Griffen is definitely faster.
Don't have a measure of speed, but you can see it pretty clearly when both are running full pace in a game.
edit: Found Deledio's 20m sprint time - 2.90 (at draft camp). Not really relevant though, as im talking over a larger distance than 20m.
edit #2: I don't think Griffen tested at draft camp.