You definitely do NOT have to take off the bumper .... I did mine in less than 30 minutes (rough estimate from a foggy mind) ... the hardest thing was getting to the 2 Phillips-head screws at the ends, one at each end.
I used a stubby screwdriver and took my time to make sure that I didn't drop aforementioned screwdriver, cuz it would be a b!atch to retrieve it.
It really is not that hard and NO you do not need to remove the whole front end. There are 4 screws on the back the crosshairs and some clips and the crosshair/grill insert comes out as one. Remove the old grill insert (have to cut the insert at the middle clips) and install the new grill insert. Then clip back in and put back the screws. The hard part is that you have to have very small hands to get the 2 screws on the left and right of the vertical of the crosshair. When you replace them you dont really need to tighten those 2 screws all the way. You have to tighten the middle 2 screws tightly. Have fun and be patient. Good luck, you will love the end result.
From Member OGB...........Do it the easy way.On each side of the radiator behind the grill there are plastic air shields going down to the splash pan.Drivers side take the plastic pin at the top out and push the shield to the middle of the car.Remove the air filter unit or if you have a cai the filter only.Now you can use a regular length screwdriver and remove the screw.Passenger side the same only you also have to pullout the clip holding some wires.Then you can push it over and remove the screw.I have large hands and there was no way that I could get those screws out.Piece of cake this way.