the cage does not run in the trunk, but why should it. It runs to the upper shock-absorberpoints, which has big reinforcements with extra steel. And all the suspension pic-up points are seam-welded
And yes it needed substantial bodywork:
New floors, new inner and outer sills, lower parts of the fenders, fixing of big crash damage (with thick layers of filler...) There was a difference left-richt of 2,5 cm in length of the car... (in the suspension.) The car has been placed on a jig to fix all this, and to be sure of all dimensions before seamwelding and welding in of the cage.
The body was much worse than suspected, and took twice the work in hours than was anticipated.
Doors, bonnet and trunklid are glasfiber, all the windows except the windshield will be lexan.
Expected weight of the car will be around 825 kg.