On Toyota trucks that mod is called the "Satochi Grill" or simply the "Satochi" after the first guy that did one and detailed the procedure. It's one of the more popular "in depth" mods that folks do. I say in depth because once you cut your grill you're committed.
Most folks get a second grill to do the mod on in case it does'nt work out.
Very good looking mod on the 3 series.