Depending on airline you might want to consider taking the train from Frankfurt to Stuttgart. That way you'd avoid the commuter stops and other airports. Timewise its probably quicker and cheaper. Plus if memory serves me right, one of MBs selected Hotels is right across from the Stuttgart train station.

I once picked up a car in Germany. A truck hit it in Portugal and totaled it. When we got home there was a check for the entire amount we paid in the mailbox. I got a new car for even less and had (most) of the transportation for a three-week vacation free.

I wouldn't recommend the Portuguese accident route for everyone, but the insurance you get with European delivery is excellent.

The train is the cheapsest and fast way between Frankfurt and Stuttgart. The MB Hotel is across the street from the Main Train Station in Stuttgart. The trains leave from the lower part of the airport and there is an express train every two hours to Stuttgart.