I was wondering if there was any way to replay the opening scenes like the very first time I installed the game. I thought the intro was pretty cool and wanted to show it to my dad. Anybody know how to do it short of creating a new gamer id ?
As far as I know this is not possible. However, I got you a link on youtube Forza 5 Opening Cinematic | Narrated by Jeremy Clarkson of Top Gear! - YouTube Hope it helps 
I was thinking this last night. The opening speech is so beautiful, we should have the opportunity to watch it again.
Well you could always go to the splash screen (title where is shows the McLaren P1 and the “Press A to Launch” icon) and do the reset to your profile. But that wouldn’t be very efficient and would be the only way to do it. I don’t see what’s wrong with just watching the video posted above, however. 0__o
Create a new profile and start the game with it.
No savegame = opening scene playing.
Now that you can manage the game files in the dashboard, you could delete the savegame for your second profile in case you want to watch it again.
I will give that a try.