Powerchip sells this for $690. I also saw someone selling it for around $400 in California which I found on one of the Mercedes forums. The best value I have seen for the modification is MTH software in Germany. Unfortunately he only seems to work with BMW and Mini Coopers. I used MTH on my Mini Cooper S and it cost $75. He email you a file and you upload it from a laptop with a special cable to hook up to the OBDII. MTH adds the timing and fuel stuff plus he moves the redline up and eliminates the top speed governor. We need to get this guy to work on Mercedes!