Can I take my retail Xbox 360 and download game to the hdd by putting the disc in and pressing x to install then out the hdd in my RGH and the game will work yes or no
MMcpick2
Get NXE2GOD and transfer it to your hdd and use it to unlock the games, it will launch straight from dash like xex menu.
As for XM360
If you wanna unlock arcade games, dlc and backup TUs then you could use this but it won't patch disc games that you've installed (called NXE format)