Pocket-Lint are probably better known for reviews of technology than cars, but today they review the Z4 sDrive 18i Roadster here:
http://www.pocket-lint.com/review/124580-bmw-z4-sdrive-18i-roadster-review
http://www.pocket-lint.com/review/124580-bmw-z4-sdrive-18i-roadster-review