So, I have found a way to mount cross hatched aluminum to the lower air dam without having to take off the bumper.
I don't know if anyone has found this out or not but here it goes.
First, you need to take of the lower air dam to access the opening from the bottom.
Then you will need a 10mm socket to take off three screws which are located right under where the air dam attaches:
Then you will take your metal grill, whatever you happen to be using and cut it to fit. It doesn't have to match completely the first time, you can trim it. But you then take it and maneuver it into this opening towards the front of the car:
I then put some screws into the top part of the bumper, but above the painted part. It is hard to explain but you will understand when you look:
Finally, Replace the three screws but this time put the mesh grill in between the frame and the screws so that the grill is now secured
If you have any questions just ask!