Actually, you're driving an S210, as W only applies to sedans.

W = sedan
V = long, stretched sedan
S = station wagon
C = coupe
R = sports roadster

just to keep it complicated ...

W164 = ML
X164 = GL

And more complication ...

If you ever see a VMI (vehicle master inquiry) at your dealer, your car will be designated E320S.

Most of the time in conversation, W210works for sedan or wagon.

Finally, prior to about 1985 W was about all that was used.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles