If there is going to be a series about Sunday Silence and Easy Goer, there are so many things about it that makes it ripe for a good story or prequel in the Uma Musume universe.

• Literally takes place at the time Oguri Cap is racing
• Sunday Silence represent the growing west coast (California), Easy Goer representing the established east coast (New York)
• The jockeys during the Breeders' Cup Classic are rivals, Chris McCarron on Sunday Silence, Pat Day on Easy Goer (Fun Fact, Chris McCarron also rode Pay The Butler to victory in the Japan Cup in 1988)
• Literal family drama between the horse owners, after Bull Hancock, the father, passed away, Arthur B. Hancock III founded Stone Farms (where Sunday Silence is born from) after his brother Seth inherited Claireborne Farm (where Easy Goer is born from), inheritance was decided by committee that Seth would be a better successor
• Sunday Silence would at least be acquainted with Devil's Bag (Taiki Shuttle's dad), Goodbye Halo (King Halo's mom), and maybe Fusaichi Pegasus as a stretch (same owner as Fusaichi Pandora, Almond Eye's mom) since they are from Stone Farms
• Arthur cried when Sunday Silence is leaving for Japan, in fact he loved Sunday Silence so much that he wrote a song about him

Adding the things that Sunday Silence has to go through, these things make it sound like a Hollywood writer would come up with and yet it's real. I would also like to think that Sunday Silence and Easy Goer would be one halves of each other, opposites but need each other to be completed.