Try on something small whether it's a mirror cover, an antenna (if you have a sharkfin style) or even a small object. It's not easy and not convenient. Four of my mates and me tried applying vinyl to a mate's 1 series coupe roof thinking it would be a piece of cake with so many guys. It's like contacting your schoolbooks but you quickly realise that car surfaces, even the roof, are not really that smooth and there are indentations, grooves, holes/ridges, antenna holes (and a sunroof in this case) which make it even more annoying. Then the moment any breezse blows or you just don't hold on tight enough, and the sticky material will fold on itself and you've just wasted the material since when you try to undo it to apply, it'll have a crease in it. It really is like contacting your school books all over again but with much bigger pieces of contact.
And I didn't have a C63- it was a C250 diesel
The shape of the C Class lends itself well to matte finishes. Not all shapes look good in matte though.