Mine is the CDC and all you do is drill a hole in the plastic top and fish some bolts through to a very small diameter pipe. There isn't any chassis tie in any of the light bars.

The only time you can get chassis stiffening is with a full roll bar like the 6 point in my 2006

 

i thought CDC required like the seats to be removed and more.

 

I'll look at my pictures from the install tonight. There isn't much to a light bar. The attachment is just at the top of the pillar. And the bars are simple light tubes, wrapped. The only reason you pull the seat is too get to the wires for the brake light

 

Think of the view from the cars following if you let the brake light operate with the top up. ....all the back windows light up red....