A. We have found that this is not necessary because: 1) large objects cannot fall through the louvered openings, and the flow of air and heat is out, not in, and 2) anything in the way of the heatflow/airflow provides resistance and slows it down. HOWEVER, for some reason, some people feel compelled to have a screen in place. If so, you can simply get a 3' x 7' piece of aluminum (non-rusting) screen at Lowe's for less than $10 (GC "Charcoal/Anthracite" color aluminum General Purpose Screen, by New York Wire), cut it slightly smaller than each Hood Louver panel, place it in between the Hood Louver panel and the hood, and let the pop rivets through the Hood Louvers hold it in place.
One of our customers put a set of Medium Hi-Flow louvers, a set of our 12" Side Louvers, and a single panel of our Rectangular Louvers. The car is a 2015 Ford Fiesta ST, that has been tweaked a bit. We think it looks awesome.
Check out this awesome Datsun 280 Z, although not mentioned those are our Medium Regular Flow Hood Louvers.
One of the coolest vehicles We have seen in a while. Louvers on a Roadrunner Hay Squeeze, from E..P. & R.P.
A Hummer H3 from J.M. Sporting our WideFlow Hood Louver, replacing the plastic non functional louver the H3 came with.