Notice that it's only Pontiac listed?
No Chevy, Buick, Olds.... And don't forget the GMC performance trucks....
As for the Sports Car/Muscle Car remarks..... I'm not defining anything, but it seems to me that in the past, I've been informed by more than one person that a Vette is a Sports Car, and the F-Bodies and Mustangs are Muscle Cars.... I think the defining factor may be that a Sports car only has 2 seats.... I believe it may also have something to with the performance factor... Meaning the Vette is made to perform in all aspects(making it a Sports Car) The Muscle Car is just made to go fast.
If anyone wants to argue these comments, you go right ahead. I don't have anything to argue with, but I'm interested to find out how other people think.