Nm?
 

In process of reading Manual for 83 380SL Chasis Type 107 and in the manual it referes to torque specifications in Nm. What does Nm stand for and will I need a special torque wrench for this purpose?

Nm stands for Newton Metre. Here's a handy site for conversions.

http://www.boltscience.com/pages/convert.htm

NM stands for Newton Meter. You can convert it to whatever tool you have:

http://www.onlineconversion.com/torque.htm

Snap! You beat me to it.

Nm = Newton meters
 

To answer the second part of your question:
Nm is the metric equivalent of SAE ft/lb. Since most mechanics work on european or Asian cars as much or more than American cars most torque wrenches these days have both calibrations engraved on them.

I hope I'm not the only one that doesn't find those conversion sites easy for anything. One NM = .737 ft lbs. So if the spec calls for 100 nm set the torque wrench for 73.7 ft lbs.