you'll probably end up having to:
1. Install the headers.
2. Fab up a down pipe from the headers to the cats.
3. Install high flow cats or put in bungs for simulators if no cats will be harmed in this process.
4. Get a crossover or X pipe.
5. From there you should be able to do the rest of the dual system with a kit from several manufacturers.
it's gonna be a mix of matching some individual parts to get you back to the crossover pipe. Not too hard for any good exhaust shop.
Good luck with your project!