Got myself a pair of nismo fender flares, no need for this now.

It's the black plastic piece that sticks out from the rear bumper.

 

interesting...ive never seen those before....cool

 

Not needed now.

 

Sorry to bump this old thread but I'm sure you will be able to answer my question. I'm searching the web and do not find anything regarding these OEM rear fender guards except your thread. I'm about to remove them to install some Nismo CF rear fins... but I'm stuck with the tiny screws which hold the fender guard. Were you able to remove them? With which tool? Sorry about the noob question but I've never seen that kind of screw before. Thanks!

 

Never mind I found my answer. These OEM rear fender guards are formally called "fillet" and are used on the 06+ GT and Track model to help prevent rock chips because of the 19X10 Rays wheel. Following are the part numbers:

Part #78863-CF40A LH Fillet: dealer cost:$12.02, List price:$20.03
Part #78862-CF40A RH Fillet: dealer cost:$12.02, List price:$20.03
Part #68399-CF40A Clips (6 needed) Cost:$.59 each, List: $.98each

The mounting hardware are not screws nor clips. They are blind rivets. Source: https://my350z.com/forum/exterior-an...his-thing.html (post #33). How to remove them: http://www.ehow.com/how_7438627_remo...nd-rivets.html