Yes, you can get rid of the volcano grey on the steering wheel IF you get the multifunction steering wheel because there's two options (either leather or painted aluminum look) that will cover the only volcano grey bit which is the Y-trim piece.

I also believe that the only piece in volcano grey that you cannot get rid of is the trim piece around the seat release button. I'll have to double check on that but I think that's it. FYI the defroster trim and air vents come in aluminum look as standard.