i don't want to temper you enthousiasm, but i'm not sure if such a mod will have much benefit, i'm not saying it can't, but without propper testing it's as likely to have and adverse effect than to cut drag.
wikipedia lists the camaro you're refering to as having a Cd of 0.338, if the figure is correct that's not all that good for such a sleak looking car.
on the other hand i do know one car wich has similar mirrors and an 0.28 Cd the opel vectra B
http://upload.wikimedia.org/wikipedi...D_sedan_04.jpg
so the setup isn't bad per definition, however the curent trend seems to be to move the mirrors away from the body.
if you want to try this go ahead and perhaps fuft test the results.