You will need the 2017 rF SX tracks. You can get that complete series here: viewtopic.php?f=4&t=45157&p=779331&hilit=2017+supercross#p779331
Thank you RaceFactory and Kyle Watts for helping me get this done. And EMF for agreeing to put on this organized race.
You can also find more information regarding the race by viewing the first post of this thread:
1/2 the texture sizes of high res
1/2 the texture sizes of medium res and a few objects deleted
1/2 the texture sizes of low res and a few objects deleted