You said you are going to run an E body in road racing and the A body is for autocross?
I not that familiar with any of this although I think understand the basic differences.
My question is why not run the A body in road racing?
The A body should do everything the E body does and be lighter?
Did the Green Brick not run road racing courses?
I can only guess there are some restrictions in modification that can be done associated with rules about classes.