Tailpipes will probably fix most of it, getting the header to steering box issue fixed will get more of it and if you do not have a crossover, either an H or X pipe that will help. Adding resonators will help. I'd do the first two then see if it's gone and add the rest in order of listing if needed.

Make sure the exhaust is rubber hung, the stock hangers were designed to isolate exhaust noise from the chassis, use them if you can. Gert under the car and very closely inspect the exhaust system for any other rubbing or metal to metal contact, do not be afraid to move the system about by hand to see if things can touch, even if it appears not to at rest.

Move the engine or dimple the tube before you fool with steering box location. Of course you ought to do a bumpsteer check to make sure the gear box is in optimal location before you move or dimple, but it's not 100% necessary, just attention to details there.