I have seen car manufacturers do strange things like that on convertible models. The previous version of the camaro was a good example. Convertibles had governs so they could only go so fast. Coupes did not.... at least that is what the salesman told me. This saleman happened to be a car fanatic himself and knows these things so I trusted his word. I just didn't trust him when it came to financing and prices!

As for the crossfire.... not sure if weight of the car has something to do with it. Maybe they feel the convertibles have less weight in the rear so they wanted the spoilers to depoly a little earlier than the coupes. Remember, our spoilers actually serve a purpose and are not just for show!