I wouldn't worry too much about weight... I mean you might save a few pounds but nothing that would hardly increase of decrease performance. If you are serious about wanting light wheels then get some volks, but then you are talking a couple grand at least just for the wheels. I think 17s are a good size for performance, enough tire to grip the road, yet not too much so you bend the sidewalls over. I would go with 225 45/17, although my 215 45 17s have worked out fine.

What do you plan on doing with these wheels? That is what you need to consider first before even looking at wheels.