EDIT: seems the mods were simply visual modifications from Forza 5, my bad
Those spoilers aren’t new to Forza. The S15’s spoiler is the Trials one, the Evo X is the Varis one, and the R-34 has the Top Secret Spoiler. They’re just like that in previous Forza games.
Yes. The wheels are HRE C109s (thanks to Hey Stack for identifying them), though, so those are new.
The wheels on the RX-7 were covered a few weeks ago. This is old news.