The Roadster and Audi R8 are both coming to market about the same time.
Both are featured in the upcoming "Iron Man" movie.
Various car journals have been sampling both recently.
There are some similarities...
Just over $100K
0-60 < 5
The Audi wins out on Luxury, and top speed, and has AWD.
The Tesla wins out on low end torque, greenness, quietness, & lack of shifting.