And what were these called on the Firebird?..........
I know, my '87 Formula Firebird came with one and that is what it was called.
When air passes under and over aero device it is a wing as in the Firebird example.
The spoiler on your Pro street and other cars has no air passing under it only over it and that is called a spoiler. In fact in the days they raced them they called it a whale tail spoiler unofficially.
So you are correct on the Firebird or the factory Fiero to call it a wing. Now anything else like you have on the PS car or even the older 2nd gen TA is a spoiler. Even the First Gen 69 TA had a wing because the air went under the wing.
What you have on the pro street was used on the IMSA cars and was called a spoiler and often used a larger lip on the back edge. This was called a Gurney strip and would damn the air flow up in the top of the spoiler increasing the down force. What you have there may help with air flow but may be limited to down force. Take a look a the real race cars and how they tuned the spoilers. A lot of work goes into these and the size of the Gurney strip can really change the amount of down force.
I know one thing I like about my bumper pad notchback over the fastback, way easier to reach and work on things in the engine compartment. Mine still looks like a typical non-restored 85 SE 2M6 but I happen to like my little Fiero coupe just fine!
Usually it seems like the opinion is fastbacks look more modern. That bit doesnt really matter to me. But I like them all for what they are. Some like fastbacks because they are a bit less angular. Some I'm sure like them because they were what was next, in 84 a lot of bumperpad cars were sold, maybe they wanted to own the "update". Maybe to some, its like hearing a song played too many times. Though.. if you go to a show today, nice bumperpads are the many times rare ones there. "GT" sounds cool, though you could get a notchie GT in 85. If I had to pick a fave based just upon looks, oddly enough (to some) I probably lean twards the bumperpad. We all have our own tastes. I even like stock or modded cars, 4 cyl and V8s and all in between. more cylinders than 8, sure!
[This message has been edited by 2.5 (edited 01-04-2016).]