Please refer to this thread.....and quote.....I was corrected and never use the term "batwing" now.
"were do people come up with these names ? if you ever called porsche part and asked for some thing like a bat wing they would tell you to call the bat cave ! that part is called a lower bumper cover ! the thing that is under the motor is called a splash shield . the pieces of plastic that are inside the fenders are called fender liners or skirts . all splash shields on the 944 body cars have some kind of cut outs . the reason there there is to cause a vacuum . as the air passes under the car and across the splash shield it causes a vacuum and pulls air thru the radiator ."
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/590368-under-tray-options-2.html