non sunroof roof bracing?

[actletpone]

Hi,
I have a 325i with sunroof, I am removing the sunroof.
There is a brace along the roof between the b pillars which is not part of the sunroof. I have seen comments that the sunroof tray adds structure to the roof. This makes sense as the sunroof tray is welded to the edge of the roof in 6 different places.

What structure is in the roof of non sunroof cars in addition to the brace between the b pillars?

[actletpone]

Found this image of two different roof braces / bow's. Top one is from sunroof car bottom one from non-sunroof. Anyone know the difference? I can only find pictures of the bottom bow from 2 door models, I want to know what is in the 4 door non sunroof cars. Bassically wanting to know If i need additional bracing after deleting sunroof tray.