To answer the OPs question about tracks. The number of tracks on Forza 6 blows the number of tracks on Forza 5 out of the water. Forza 5 had 14 tracks on release and released two more through free updates totaling 16 tracks. Forza 6 came with 26 tracks
out the gate not including the different configurations of each. So yes much more content in 6 compared to 5.
the link via MS-Xbox1 to the nascar-24 car expansion and tracks doesn't work yet...tried a few minutes ago via pc direct online... normally all of the tracks available are great in Xbox1 forza6 ... I am spoiled re forza 4, my son is too, as we race online
against one another in our spare time.
here's the link to prove MS-Xbox online is pushing the nascar expansion out...maybe somebody clicked "go" when the should have clicked "Wait" when releasing this link... looks like $19.99