Roll cage tie-in plates?

[MaxD]

A well designed cage stiffens up a chassis considerably. Tying into the A-pillar is always a good idea, but rules might prohibit it.

The local cage builder of my cage (Tatum Racing) does this. They have built many Boxster cages with no windshield cracking.

[maytag]

Like Max's, the cage for my spec boxster was also built like this, with no negative side-effects. (mine was built by a hot-rod shop in CO)