I had a set of autocross wheels 16" Flik's that were barely 14 pounds on my old Miata. Five spokers in gun metal, car handled great with these.
A guy with a red mini cooper S ended up buying them and they looked better on his car than mine. I don't think you want to weigh down that supercharger with 20 pound wheels.
These are the wheels
http://www.cardomain.com/ride/2547450
this is the site I picked them up.
http://www.edgeracing.com/wheels/flik/