If you wax it once or twice a month the wax creates a protective coat over the paintwork.
Also the car-wash brushes you can get don’t damage paint.
I fixed my other problem…the engine noise and low mpg. Just changed the air filter and ran a fuel additive through the system. Then sped down the highway at 100kph in 3rd gear. MPG is back up to about 45-50mpg.