Steering, suspension, and wheelwell restoration
IMO.....
If you are building for the Javitt Center trophy....clean sheetmetal with body color.
If you are building for looks and practicality. .....black it out with rubberized undercoating....especially where the stones would bounce off the metal. Makes your wheels pop out, deadens the road noise, protects from stone chips.
Or a combo (like the factory).....body color overspray with some sound deadener spattered on by Ray Charles as he BS's with his buddy on Thursday afternoon. (No workee on Friday)