Landing plates are done, framing up the rear support bars. The tape shows where the harness bar will run, placing it that far back keeps the harness in the 0°-20° below horizontal range harness manufacturers recommend. That angle is especially important when using a HANS device.
We'll add the diagonal bar next. Once it's framed up, we'll be adding some bolted joints (machined interlocking joints, not a sleeve or anything like that) so that it can pack flat for shipping. It's not necessary to get the assembly in or out of the car, but the additional manufacturing costs will be negated by the reduced shipping cost. Shipping these things everywhere on a pallet via freight will get real expensive compared to a large cardboard box UPS can deliver.
Jake