I hear that spoilers, most of the time, create downforce at high speed traveling for better handling ... so does the factory spoiler for the sedan make a difference and create downforce or is it just cosmetic?

If it is just cosmetic... then they have failed the test.

 

the spoiler with the underbody diffusor will allow the rear to have zerolift

it only provide enough downforce so it have zerolift not anymore

 

If ya think about it for just one second, you'll answer your own question. How many "after market spoilers" have you seen come WITH underbody diffusors. Why bother including the extra pieces if they had no effect. Granted they're only recycled bathroom cups/tooth brushes....BUT as I said "why bother"?. Yeah they do work.....seems the effect is truly noticable at about 8o mph on the twisties. Get it Dude...the install is simple if you've got good basic skills.. JBX

 

On the sedan, the rear deck spoiler and four underbody diffusers reduce the coefficient of drag from .27 to .26; they also reduce the lift to zero.


Not aware of any other mainstream carmakers that actually test their spoilers the way Infiniti did with the G. Kinda cool.