Loved the looks of the RCZ when it appeared, I like the double-bubble roof on it. One of the main features I love about the Z4 coupe is the similar groove down the middle of the roof.
As for sports cars with no pedigree or technical prowess and with a 'lack of power', there's a huge market as I discovered recently with my mother-in-law. The original brief for finding her a car was a sporty convertible that was really cheap to run. (after looking through all my suggestions, they bought a Renault Wind 1.2 that she'd quite liked after she'd seen one in Paris).