You can try

http://www.renntechmercedes.com
http://www.superchips.com
some people on this forum have tried the Precision Auto Designs (PAD) chip as well. http://www.precisionauto.com

Do a search for Chips...one of the threads have pictures of how to do it.

Hope that helps...

__________________
Rainmaker
93 500E, 43k mi, Pics of upgrade parts
Evo II Wheels on Dunlop FM901 235/45x17s
94 Facelift
RennTech CF Airbox
RennTech ASR Defeat
RennTech Chip
1st Gear Start
97 Range Rover 4.6 HSE Vitesse, Yellow, "Tonka" (sold)