Ok, follow on question concerning cage building, as I'm getting close now.

I've seen past discussions about rear braces passing through the rear trunk bulkhead, and ITCS examples which support this. I'm looking at the 2011 GCR right now, and the only thing I see that pertains to rear bulkhead is in 9.4.G.6: "Any number of additional tube elements is permitted within the boundaries of the cage structure. Such tube elements may pass through any mandatory or optional bulkhead or panel separating the driver/passenger compartment from the trunk/cargo area/fuel tank/fuel cell area provided the bulkhead is sealed around such tube elements." This seems to pertain only to additional tube elements, not the mandatory elements of the rear bracing.

The section pertaining to the rear braces is 9.4.B.2.c: "Cars must have 2 braces extending to the rear from the main hoop and attaching to the frame or chassis. Braces
must be attached as near as possible to the top of the main hoop (not more than 6 inches below the top), and at an included angle of at least 30 degrees."

On the E30, this rule should be able to be satisfied by using the front of the rear wheel tub as a mounting (chassis) structure with some finessing of the angles. I'd prefer to pass through the rear bulkhead and mount to the rear shock tower. What gives us cover for passing through the bulkhead?