Wouldn't be particularly competitive, would it? Even assuming people who ever participated are driving game aces that all knew the entire 4-hour track start to finish we're talking about finishing times in the many many minutes apart even driving identical cars. Doing it vs AI wouldn't be any better for the same reason. Unless this is some kind of time attack sort of thing I can't see how it could ever be an online event.
But hey, this game is back on my radar after me generally dismissing it as a NFS-GTA mash-up designed to shoehorn players into always-online games along with Microsoft's original plan that had no reason to be always-on (though I'm still not seeing the point). I gladly welcome insanely ridiculous challenges like this as someone who has completed every GT endurance race ever. Especially considering you'd want to practice the route at minimum 1-2 times first to even have the vaguest clue what was going on this could be an awesome time investment. Well, assuming the entire route isn't straight expressways and random traffic pattern generators... And the engines sound proper, and we can play a decent soundtrack to prevent boredom.