^^^ Good point. Hopefully the car was confirmed "square" before painting.
We used a surface plate for the vintage TA cars, but those got a lot of pipe.
To me, a unibody car really needs a cage - at least 6-point - if it'll see the forces that drag racing or road racing puts into it.
After thousands of passes, my Duster's doors still close like a new car; a buddy who had an un-caged PS Cuda in '70 had a twisted unibody after 1 season.
In my car's case, only way to get into the rear seat area was through the right side, due to no RF seat.
And I'm not a big guy at 5'11" & 165 lbs.
In any case, I keep thinking, "what adult wants to get into an E-body 'Cuda's rear seat" ?