First of all it an "eBay" item which throws up a red flag for me. From the pic it doesn't look efficient, small hose along with whatever purpose the box does. I can understand bringing more fresh/cool air into the intake area and know that works. To do so you'd need at least 4" diameter hose hooked to a duct in the lower area of the grille run thru the radiator support kinda like what Sean has come up with....woops that's a secret.
Gary