I realized that the initial photo probably didn't show it very well, so I've edited it a bit:
We have a cast "bellhousing" section that bolts to the turbocharger exhaust housing - essentially a shorty downpipe. This runs back and bolts to the stock location secondary cat. This maintains the stock exhaust profile.
So any exhaust systems, stock or aftermarket, that would have bolted up to the stock exhaust manifold will be able to bolt up to our turbocharger kit.