Transfer Gamertag to USB. (NOT A GAMESAVE)<br />
Extract the 584111F7.gpd file to the desktop, and then into the editor.<br />
Mod the things you wish.<br />
Replace the old .gpd with the newly modded one.<br />
Then rehash and resign.<br />
(Go in a game, and it will be the same, but increase the level of the leaderboard star you edited, and then exit the game, it should update to the modded one once you leave, plus what you increased it by when you played.)<br />
Remember to play it safe.