grey interior looks great, and it also make you feel roomier because of the light color, it will certainly looks good on dark color car.
however, I do have a mb c320 silver with grey interior, and trust me, it just too hard to maintain. you have to take care everytime your butt sit inside the car, even worst if it your friend's butt, which you can't do much about it. I ended up with black stain everywhere and it never goes away
