I really don't know anything about tires, but I do need new ones.  Do I have to buy the stock 215/50 17's or could I get away with some other size.  Its my daily driver now and I do live in the upper midwest.  What do those number exactly mean anyways, I know the 17 is rim size.  Any suggestions on other sizes because I am having trouble finding exactly that one.   

so what size could I get away with on a venge with stock 17's and not rub or ride like crap.