What Scott said... Find a 255, 275, 305+++ width in a <50 series tire in a 14-16" and the race/solo community will beat a path to your door.
And actually, for the same level of stiffness, rubber probably weighs more than aluminum...
17s remain one of the best bang for your buck wheel/tire combination form both a cost and performance perspective for 3000+ lb. street cars. Miatas are another topic...