Well just to finish this debate off, I just ordered my 7x17 Wolfrace Octanes in Hyper Black...plus a 285mm big disc conversion, which is the reason why I needed bigger wheels in the first place. Once Ive worn out those I might go for the 305mm conversion...
So to add another angle to this argument, I am running 17s for the exact same reason that all big wheel racers (touring cars, WRC etc) run big wheels - because they have to to fit bigger brakes inside. Ive got the bonus that they look the nuts as well though!
Well see what the handlings like, but to be honest, Im used to my Clio rattling your teeth already - with a 35mm drop on Koni adjustables and Powerflex poly bushes on the anti roll bar and lower arms its a pretty harsh ride anyway.