As I expected, here is the easy solution:

"One of these includes the question of size, with GTA V being the most ambitious and generously proportioned GTA game yet, dwarving Red Dead Redemption and GTA IV in scale.

This means that the Xbox 360 version will ship on two discs, one of which will be a mandatory install disc that will require 8GB of free space on your console's HDD. The second disc will then be used to subsequently play the game, which means no having to interrupt your GTA V experience to swap discs. Players with 4GB consoles can use a 16GB USB 2.0 Flash Drive for the install."

http://www.xbox360achievements.org/news/news-15424-Grand-Theft-Auto-V-To-Ship-on-Two-Discs--8GB-Install-Means-No-Swapping-Required.html

What a downgrade.. Disk swapping is an awesome feature.. Makes me use muscles i rarely use..

Another victory for Blu-ray.

RolStoppable said: Another victory for Blu-ray.

Which will still have a mandatory install on PS3.

More like another victory for mandatory installs.

So they both require mandatory installs, then you play from 1 disc... It is the same on both, the rest of the Q&A has more interesting things

http://www.rockstargames.com/newswire/article/50871/asked-answered-gtav.html

Huh? Mandatory install?

I'm a bit confused - I'm pretty sure I once read that Microsoft forbade mandatory installs for Xbox 360 games? (so it would be ensured that each Xbox 360 game runs on every Xbox 360, even those without a hard drive)

That dvd man

ArnoldRimmer said: Huh? Mandatory install? I'm a bit confused - I'm pretty sure I once read that Microsoft forbade mandatory installs for Xbox 360 games? (so it would be ensured that each Xbox 360 game runs on every Xbox 360, even those without a hard drive)

That was kinda thrown out the window with Halo 4. It had a mandatory install for multiplayer.

You don't need a HDD anymore. You can use a USB memory stick for extra storage.

I would have rathered they did disc swapping... 

I'm fine even if it's 4 discs and swapping :D