Rota wheels man, there gonna be best bet. If you want light, then rota slips are gonna be a good way to go.

here is a pic of a sol with black slips

Another set that I like is the subzeros, dont have a pic with them on the car though.

As far as seeing a difference in fuel millage and accelleration, your not gonna notice any, if anything youll get better handling from throwing a wider tire, but thats about it. Now if the car is more exstensivly modified then the effect might become more noticable.