In the teaser, when Crockett and Tubbs are on a stakeout, it's obvious Don Johnson had to loop dialogue in at a later time. We clearly hear Sonny saying the words, "You can't do an honest day's of work in this neighborhood...", but as he turns his head his lips aren't moving.
Watch closely while Crockett drives his Ferrari through the night - it is a shot filmed from Season 3 and the spiky hair style he had only in season 3 is noticible - and completely different than the longer locks from the actual episode.
The German episode title is "Die Killer".
Music: "Forever Tonight" by Jan Hammer (at the very beginning); "Crockett's Return" (a variation of Crockett's Theme) by Jan Hammer (while Sonny is driving back from meeting his son); "Race Against Time" by U2 (towards the end).