ERROR ALERT!!!
In SLK, the "k" means "kurz" (= short).
"Kurs" means course, as in biology 101 or track as in race track...
In the UK (at least according to CAR mag and 5th Gear) the first SLK had the reputation of being a "Hairdesser's Car." (Translation: a chickmobile or a ride for the limp-wristed, light-in-the-loafers set...)