Why not package the Kammback as 'K-wings' similar to large WRC hatchback wings. Instead of performance downforce reduce rear wake drag. It is disguised as one but there is clear top to continue clean flow. Hopefully it is not too alien to young gearheads approval. And how about outer diameter wheel covers over OEM/alloy wheels. Brake cooling and 'cool' factor somewhat left intact.
I speculate the Fiat/Chrysler 500 will be a sales winner for many performance/economy buyers so why not start there.