Dear JCE,
As an inexpensive (I know it's relative) enhacement for your brakes why don't you consider simply swaping out the pads for some carbon-kevlar racing pads. I did this on my SLK and got a noticeable improvement along with the added side benifit of no brake dust. Be careful to stay away from "ricey", fly by night, pad companies. I go with Porterfield Racing. They can be found on the web at http://www.porterfield-brakes.com and they have applications for almost all Benzes.

Just a thought on how you can affordably do both upgrades, I know I hate to wait and save up for anything, especially if I can have it NOW! Later. Paul.