Now I'm not suggesting the 91 Firebird GFX has its roots in motorsports, and making the 91 much more than a swan song cosmetic makeover to help keep the car looking contemporary, however (lol), notice how the side GFX of the more purposeful McLaren has a flick up ahead of the rear wheel that continues to the rear bumper.

Not completely unfounded that the 91 GFX may have had, or been inspired by, some sense of function.

Hmmmm....

 

There's gotta be a reason a 92 TA was able to go 300 mph.....
https://us.motorsport.com/general/ne...ville/1768552/
https://www.hotrod.com/articles/4349...tiac-trans-am/

 

hmmmm. I can nearly see how it how could provide some downforce for the rear as it captured and channeled air along the lower sides of car. Though I suspect and meaningful downforce would be over 100mph

 

It's always been about aerodynamics, or as the old '82 Firebird commercials said, "see how Firebird CHEATS the wind..."

 

Nice looking Firebird.