On the GT model you can simply pull the grille out, i did on mine. On the V6 however, the ones with the chrome around the grille at least, you do have to remove the bumper. There is no way in hell you would get those clips off with the bumper on the car, unless you did just pull the mess out of it, and at that point you would risk damaging the bumper and/or seriously scratching the paint around the grille.
As far as the cutting; if your V6 does not have fog lights there are simply 3 support ummm "pillars" i guess we'll call them. Just cut at the top and bottom, flush, and you're good to go; the stock grille could be reinstalled after this.
On my 5.0 however, i did have fog lights, and you do have to do a bit more cutting, i tried my best to leave what i could of the mounting points, but i doubt they would ever go back on.