Split from the Luxembourg thread - this is the story of two DeLoreans on the Nordschleife at The Nürburgring.
OK - well so far I have 3 cars confirmed for the Autobahn route (no limit!), with a short stop in a quiet village in Germany. Likewise we need to get back as early as possible too, and we've got further to go. The drawback is that we'll have to leave Vianden at about 11-11.30am on the Sunday. This gets us to the lovely village of Nürburg at about 1pm. 30 minutes of gift shop/standing around/cup of tea/fag, then onto the "toll road" for 13:30 precisely. 13 minutes later we hit the road. Let's say that's 14:00 - worst case. That would get you home at 17:30. The quickest route for you is to go "straight up" at Kerpen on the map above on the way back.