I painted the rear section of the exhaust in an aluminum colored exhaust paint and put a heat wrap on it in the areas it goes over the axle because of the proximity to the inboard rear brakes, the gas tank, and the fuel lines.
For the gas tank, after it dried out from pressure washing, I used a shop vac to get the rest of the dirt and debris out of the tank and then used a tank sealer to coat the walls and prevent any future rusting. It seems to hold water just fine, but was surprisingly dirty. I will be putting two fuel filters in the car, one on the high pressure side before the fuel pressure regulator, and another between the regulator and the engine. My last fuel pump was able to handle a lot of debris so I'm hoping this one does the same. The bolts will be welded to that flat piece of sheet metal. A tiny cheesy looking but very effective and very inexpensive, while maintaining a low profile for these shallow tanks.