It's pretty much a given that if you want to win in Formula-1, you get Adrian Newey. Not Vettel, not Alonso, not Jesus, Newey! His cars won five championships for Williams, one for McLaren, and so far three for Red Bull.
The key to his success lies in his innovative solutions, like his pioneering exhausts between 2010-2011 on the RB6 and RB7. But while they have certainly worked, helping Li'l Sebastian to a pair of his trophies, they didn't perform too well as far as aesthetics go. You need the Italians for that.