I guess I did it completely wrong, I went with the stock tire size (205 40 17) on the stock rims and got Pirelli Winter Sottozero tires. I did this mainly because I wanted the handling to be close to stock when the pavement is dry or wet. I haven't driven these in snow yet (supposedly getting an inch or more tomorrow) but they are really solid at high speed in wet and dry conditions. Of course the overall grip is not the same as the stock Bridgestones, but there is plenty of grip and it's predictable if not a bit squirmy. Hopefully the stock tire size/stock rims won't prove to be a poor choice this winter, I'm planning on putting my summer tires onto some new OZ wheels in the spring.
http://www.tirerack.com/tires/tires...utoYear=2014&autoModel=Fiesta ST&autoModClar=
http://www.tirerack.com/tires/tires...utoYear=2014&autoModel=Fiesta ST&autoModClar=