2008 Audi RS 4 quattro 4dr Sedan AWD (4.2L 8cyl 6M)
Overall, this car has been a pleasure to own. I previously owned an '04 S4 that still brought smiles to my face after four years. The RS4, however, really is a very different beast. The engine has a very distinctive character. Not only is the sound phenomenal but it just simply has more oomph throughout the rpm range. This is especially true above 5000rpm where the tach rushes to redline. Living in the northeast, the car has been wonderful in snow and ice. It is easy to drive even with the "S" mode activated (I had read where this made smooth driving difficult, but I disagree). The ride can be harsh but is superior to the S4.
Stealthy appearance - I have the titanium package which removes some of the differentiating features compared to the A4. Engine is phenomenal as above with a great sound. Usual Audi quality interior. Four season capability.
Make the "S" mode the default setting. Would still welcome even more power.