FCS H.9.D requires that any suspension arms that attach directly to the frame be boxed in to help prevent cockpit intrusion. This again is a copy of the FF rules, but was not part of the required construction rules that covered FC also. It was not stated as a requirement in the FC rules.
As such, most, if not all, VDs are not up to snuff in this requirement. I don't know exactly what years they did not box the mounts, but I believe that it was quite a few.
The question will arrise as to whether or not this rule should be there if it was not a requirement for FC, the rules upon which we tried to draw for this class.
I'd submit that while there is some logic to recinding this rule since it would require additional work on many converted cars, the additional safety that it provides is of a higher order than the inconvenience of having to do the modification.