I have 1.5 Gig per month to mess with , that gets chewed up much too quickly.
My Brodband is super super slow in this area due to fringe reception with my dongle.
Its just so much more convenient and quicker having my own copy of the race.
I can watch the replay as many times as I wish immediately after the race.

I actually did have a play with that Darfish , but I think it didn't work unless you were actually on line.
Plus I'm not sure if there is a substantial delay from when the race video being provided.
At the minute , I haven't even bothered installing Silverlight.