I do like the smaller size but tire availability is the concern. I'm currently running 16" Superlite replicas with Toyo R888 in 255/50R16. I picked out this total package and there are very few other tires in that size.
Have you seen the RS wheels? I really like the black wheels with the center caps but would prefer 18" diameter.
http://roadstershop.com/wheel/rs-oe1-wheel/