I just dipped my grill yesterday! You have to remove the bumper cover, which is surprisingly easy.
There are C clips under the hood for the top, count 4
9 C clips on the bottom under the car
And two C clips in the wheel wells.
Then you need to pry the cover gently from the wheel wells toward the front. It feels a little sketchy but just be careful and confident. If you have fogs, you'll want to disconnect them at this point. I recommend two people to remove the final assembly, but I managed by myself, with an old comforter on the ground to set it on.
It's almost exactly the same process as the WRX bumper cover removal here:
Then you just unscrew the grill from the bumper for spraying.
http://i.imgur.com/kB7GgUZ.jpg