KIND OF NEW TO THE MUSTANG WORLD AND MODDING, BUT WHEN IS A TUNE NECESSARY OR OPTIONAL. ( JUST WHEN YOU ADD A HP CHANGING MOD) OR WHAT, HAVE BEEN READING FOR A WHILE AND SEE CERTAIN ( MANUFACTURE) MODS DONT NEED THEM BUT OTHERS DO. JUST KIND OF CURIOUS AND CONFUSED. IM STILL STOCK BUT HOPE TO MOVE UP SOMEDAY, MAYBE AXLE BACKS FIRST. (GOTTA CHECK WITH THE BANKER-WIFE. ALSO WHAT FUEL SHOULD A STOCK GT BE RUNNING. HIGHEST OCTANE AVAILABLE RIGHT? :usa PEACE AND THANX FOR ANY INPUT!!! :rockon TIMBERWOLF