Stick with the 195 size. If you go 205 on the 280, it will decrease your acceleration. Don't ask me how I know These cars are geared high anyway for the Autobahn, so the get up and go from a stop is not as good as it could be. Look at Tire Rack. They have a pretty good selection and you can filter them out by class. Even if you are not in the States, you can get an idea of what is out there and then search for it locally.

My 2cents worth.

Glenn