[the shadow]

I started looking at FF's an an option for buying a first cobra and wanted to know what if any differences there are between the chassis's and bodys from the mark I to the present model. I know they dropped the foot box at one point and thought they did a body mod too? I understand the newest models have impact crumple zones built into the frame. did they change the body contours in any way etc, a lot of people talk about being able to see the difference in a FF body vs a superformance or backdraft, whats the differance?
personally I think the FF's look flat across the hood/windshield area where as the superformance and ERA's have a rounded crown (which I like). just asking as I have not seen 3 different types of cobras all parked next to each other locally its all FF's.