Kall of the Krauts

What's going on right at the end of this German Opel GT commercial when they go "ie yie yie yie"? Is that the mating call of Kraut hippies? Are they trying to be Japanese, since it sounds like something Ichiro would yell in Godzilla's Revenge. (Be sure to watch the trailer there. I love that movie.) I keep playing that Opel ad over because that sound makes me giggle so much. And who wouldn't want an Opel GT, the MiniVette?