A '71 Roadrunner is about 3 fiero's long and probably almost 2 wide. How in the heck do you get that mixed up?
I mean, I love that bodystyle, I have a '71 Satellite Sebring Plus. But they are not small cars. :D
As for the other misidentifications, my Challenger is a "charger" about 90% of the time to the general public. I did once have it called a Cougar, that was kind of sad.
The Duster/Demon is usually mistaken for a Nova. But I have a lot more people ask me "what is that" with the Duster than I do with the Challenger. But the multi-colored bodywork and the Demon "tribute" work I've done probably confuse people. Once it's all the same color I'll bet they'll go back to just assuming its a Nova. ;)