It'll take up a surprisingly huge 30GB of space. Yowzers. Probably a good thing they start letting you download it early.
To be fair most people have hard drives big enough to handle those kind of figures these days, but it's still a bit cumbersome. Even with all the extra content the PC version comes with.
Called Dead Rising 3: Apocalypse Edition, it bundles up all four of the Untold Stories of Los Perdidos DLC packs (essentially extra mission from the point of view of other characters), and also adds higher resolutions and Seam cloud and controller support.
You can Dead Rising 3: Apocalypse Edition for 10% off. If you buy it now it might even finish downloading before its release date this Friday, September 5.