Ok.

If you are choosing those cars, I can't help with the Saab or VW.

However, over the last 2-3 years I have had the opportunity to drive some decent cars on autobahns. I have had c and E class merecedes, audi A3 and A4, and a BMW3 series.

I like the way audis drive over the mercedes. They are more stable and handle better. They are not as comfortable though. This last trip, I just had a BMW 320d. Although a 2L diesel, it had a top speed of 225kmh. I saw a little over 220kmh on the speedo. I drove for long periods of time between 180 and 200kmh. The BMW was the only car I have driven that was both confidence inspiring at speed and relaxing (comfortable) to drive at speed.

Go for the BMW.

-Dana