I am missing the hood pad from my 72 SL for as long as i've known it the car (20+years). The paint does not degrade sooner on the hood then on the body so for me that is not a concern. as far as noise goes, roadster are noisy so i don't blame it on the pad, with a diesel i would think otherwise. One day i'll put in a pad because it should be there but i doubt it'll make much diference at all.
1982 300D Turbo