Always check the price of brake components before buying an AMG car - you can do so right here on the website. Some AMG cars have front rotors which cost in excess of $1K each, so a 4 wheel DIY brake job is a $2K proposition, and perhaps $3500 at a dealer.

Don't know if the S55 falls into this category or not, but it's the kind of thing you want to know before buying one.