Turn 10 studios had annoyed some potential buyers after announcing they would have to have install the DLC from Xbox Live before they could enjoy the next-gen action.
Now, following a backlash from fans of the series, Dan Greenawalt of Turn 10 said players can get started on the game straight away, but they download will be necessary at some stage in order for gamers to get the most out of the driving title.
The extra content includes extra cars and tracks that won't be present in the disc-based version of the game, as well as extra Drivartar data.
Drivartar, of course, was one of the key Forza 5 features Microsoft highlighted at its E3 keynote.
It allows your driver to gain experience points and compete in races while you're not playing the game. It also gives you the opportunity to race against more human-like AI opponents within the game.
Turn 10 says the Drivatars contained on the Forza disc will be trained by them, but connecting to the internet will introduce other real world 'clones' into races.
There'll be enough to get you by, but downloading the extra content will be a must for getting the most out of the game, the developer said.
"In the beginning of the game, the player will be racing against Drivatars that are contained on the disc and were trained by the [Turn 10 development] team," Dan Greenawalt told IGN.
"While playing, the player will be asked to connect to Live in order to download a completely fresh set of player-created Drivatar opponents – it’s not a lot of data, but the download contains enough Drivatars to cover all difficulty settings. Connecting will also download new content – but the vast majority of the launch content is contained on the disc.
"This download is simply additional cars and tracks. The gameplay is not blocked while downloading the additional content; it’s done in the background just like disc install."