• Porsche (for free... after purchase of game)
  • Rally di Positano (the yumps, man, THE YUMPS)
  • The Sun (specifically at Nurburgring and Fujimi Kaido)
  • Less Aliasing (and in general it looks better [to me, at least])
  • Probably other reasons

Side note: why do Fujimi Kaido and Nurburgring look markedly worse with each iteration of Forza? Turn10, get on that.