When I take my car for inspection I have to have a front plate. My solution allows me to easily remove it when not needed (not that I would very drive my car without one). Take a piece of foam rubber approx the size of the plate and about 4 inches deep, you glue it to the back of the plate. Cut 2 grooves in the foam one in the top and one in the bottom, you can now stuff the foam block into the
oil cooler vent and it will be held in place because it is compressed to fit in the hole and the grooves hold it in place. It works great but will restrict the air flow, you car may have no problems with the air flow restriction. Play around with the size of the foam before you glue it to the plate, it works great. Looks good to, not as good as without it.