1. I would say the 911 is a luxury sports car. Why? Because it is a sports car, but it is also luxurious. 2. You said a 70k car should have a 70k interior. A 70k interior implies it is going to be a very good interior. I consider a very good interior to be luxurious. 3. F40, F50, other typically higher end Ferraris. It's not that they're bad interiors, but spartan for sure. I mean not even a radio for christs sake! 4. Supercar by it's very nature implies it is a fast car. If Honda made a civic model with one of the most outrageous body kits imagineable to make it look exotic but it still has a 200hp I4, would it be a supercar? Obviously not. I don't understand what you mean by sports car billing doesn't equal sports car interior... Are you trying to imply sports cars in general are supposed to have nice interiors? Look at MGs, Sunbeams, Austins, ect. Most of them didn't have nice, or decked out interior for their day. Neither does they Miata today.