Less rotating mass = better acceleration, for sure. Less unsprung weight helps the car handle better, too, for sure. Rota makes some good wheels. I imagine you could drop an inch or so off the wheels, if you REALLY felt the need to reduce unsprung weight. Just a few suggestions. Also, Konig Heliums, which are lightweight, may come in 17 inch at the right pattern and offset, but I'm not sure.