On the W201 (190), there are 4 drain lines, one at each corner of the sunroof pan. The front two tubes run down the A pillars and empty into the corners of the engine bay into rubber funnel drains that goes into the fenders. The rear drain tubes exit from the C pillar sail vents. I found that the "fish tape" that I used to use for installing wiring worked pretty well for the 5 or so feet that the tubes run. The tape, available at most home electrical depts., is a bit more stiff than line trimmer cord.