W203/w204?

[Pontyprop]

As a newcomer to this site and MB ownership (anticipated) I note the terms W203 and W204 for example.
To what do these refer, - is there a reference site to identify these terms please?
Please excuse my ignorance!

 

[Rory]

http://en.wikipedia.org/wiki/Mercedes-Benz_C-Class

There's a chart of all the W numbers at the end of that page.

 

[Ellsy Tanners]

These indicate the first 3 digits of the chassis number, and determine the model.

All of very new c class's as of this year will start chassis number 204---- (Latest Shape) previous shape is 203-----.