You ripped it from Klaytons WF beta mesh?
I think MaxD man was working on World Finals 8 buddy, we migth need to confirm that.
About WF 15 i was painting it for Monster Jam Fan, i don't know if you remember it but he told me he modeled it when in reality he just imported Klayton's WF beta mesh to blender, after that there was a whole rant and decided to kill the project. In the other side i think Tharindu was making 14 & 15 i migth be wrong but he has been dead since i don't know how long and can't confirm it.
So in few words i would continue to work on 15 JUST if Klayton is ok with me using the models that he made (that i already textured) for racing and making freestyle by my self.