While you are under there and the under-shield is off, if you want to pop out the driver's side lower grill, here's how...
2817 - Remove the retaing clip. My finger is on it (oh, yeah. Something on the plastic pieces when removing the silencer can scratch the hell out of your hand - were some gloves for protection
2818 - Once the clip is remove, pulling bit on the bottom so the bottom clip - which are molded to the bumper - disengage.
2821 - The clip and the plate removed.
Now put everything back in...
2820 - The "space" left after the silencer is gone. I'm not going to cut-up and put the top part of the silencer in there. The guides around the bumper guide cool air cross the radiator. And the fact that I yank the lower grill out will allow more air into the void. Good enough for now.
Later, I'm going to try and manufacture an "air guide" from the lower grille to the openning into the air box. Guess it's time to learn about plastics and possibly fiberglass.