Is this working out for you? It is my understanding that the entire front frame is different between the C2 and C4. Different mounting points for the front suspension (which is also different), different stiffeners, different mounting points for accessories (for instance the C4 uses a split gas tank), different trunk tub (to accommodate the front diff.) etc.
They only have one part number for the body because you can only order a replacement body for the current production model and you need to give them the full option label so that they can build the body to match your specs.
I may be wrong but anyway, that is my understanding.
Many guys convert a C4 to a C2 (basically removing the front diff and half shafts) but I have never heard of anyone going the other way.
Last edited by tharbin; 10-11-2016 at 03:29 PM.
Reason: Added sentence about C4 => C2 conversions