basically i'm looking at $800 for either 16" steelies+Dunlop Winter Sport 3D's or 18" of the same tires (no wheels). so it's a wash to go either way, with the exception of $25 per winter/summer swap on the 18" wheels.
the guy also mentioned that i should retain much more of the handling performance with 18's than 16's, and the 18's were his recommendation.
so the 18's is what i'm going to go with, seeing as there is no price difference. i could possibly save a few bucks by going with Tire Rack, but they won't give me the service that my local place does. if the winter months chew up the stock wheels (which i doubt..?), then it's just an excuse to upgrade to a nice summer wheel.
I priced out the same 16" package at TireRack and it came out to $624 before shipping. Even if I were to replace the stock 18s with something else down the road (which I might), it STILL makes more sense to just get a dedicated set of winter tires & wheels - less hassle, no swapping of tires and better resale. For the same money as a set of 18" winter tires, you get the steelies to boot! I also have the option of selling the stock 18s to someone willing to pay for them because let's face it, there's a much bigger market for used winter tires w/steelies than there are for winter tires on MS3 18s.