my slk has the W and S settings, The W setting is for winter driving
and it starts at second gear (which prvents slipping and sliding) and
the S stands for summer or Sport driving,  whchever, and this one
starts in first gear.

As you have probably read in your manual C is for Comfort and S is for
standard.

In Comfort mode the the transmission shifts up earlier and does not apply
full throttle. Ergo Standard mode is the best for acceleration.

Ash

  you've already seen the explanation, however I always thought that 'S' stood
for 'sport'.... mind you the difference is minor at best... as previously
explained.  In my B class I notice it holds that rpm at about 3k rather than
2k... big deal

cheers