GTA V Xbox360 Install Issue Solved Sort-Of

Rockstar Games recommended against installing Grand Theft Auto V's game disc to your Xbox 360 hard drive -- it creates performance issues -- but Digital Foundry has discovered a solution. Storing the installation disc's data to your hard drive, and the play disc's content to a USB drive, apparently smooths out any texture pop-in or lag problems. This allows your machine's hard drive to worry about the install disc's data.
Your best bet is, as usual, the bigger/faster the better -- make sure your USB flash drive is at least 8GB. Double the space will go a long way in terms of making sure you have the size and speed necessary to make GTA V run at its absolute finest.