It may even be bumpier than the current standard for German public roads, which are generally of exceedingly high quality.
Most people know about the unrestricted sections of the autobahn, and it is certainly fun to flog a rental Opel Corsa with a 1.0L 3-cylinder engine to 160kph, while being overtaken like you were standing still by various Porsches and big BMW/Mercedes/Audis.
But the real fun is that the general speed limit is 100kph (62mph) off the autobahn and outside of towns, even for relatively small and curvy roads. Couple this with the generally very high standard of German roads, and you can have a hell of a lot of fun within the speed limit.
I'm in southern Germany at the moment, visiting my girlfriend's family. The winding roads in the Schwarzwald area are absolutely amazing to drive, even in the little Corsa we're renting. You have to really flog it in second gear to get any speed going uphill, but it is so damn rewarding. And you notice so many other people doing the same, in all kinds of cars and on motorbikes.
I know it's a bit of a cliché, but driving enjoyment really is part of the German mentality.