Defending Global Rallycross champion Tanner Foust must overcome one more round in the GRC series before he can keep his title another year. That will come Tuesday night in Las Vegas at the GRC Finale outside the Specialty Equipment Market Association (SEMA) trade show. We tried to get Foust to talk a little smack against his closest rival Brian Deegan but that proved diffitult. Foust is one of the best rallycross drivers in the world but he refused to press that title on everyone chasing him. Listen…