I find studs rather useless, Spin like crazy on dry pave. I'm running 185/65/15s on my 2001 TDI compared to the 195/65/15, Narrow little tires cut threw snow and slush nicely, and roll good. Now back to studs, if you do alot of pave road driving, don't waste your money, if you live on backroads and dirt roads that get hard packed with snow all winter then Maybe stud them.
155/85/13s would be a perfect tire for the winter, and there isn't alot of resistance with that sizes(put a set on my GTI this summer for fun and burnt them off in 1 after-noon of driving)
Now where in the US studs are allowed and not.
Ten states prohibit studded snow tires: Alabama, Texas, Florida, Maryland (exception five mountain counties), Louisiana,
Hawaii, Illinois, Minnesota, Mississippi and Wisconsin. The District of Columbia and 33 states have seasonal restrictions: Alaska, Arizona, Arkansas, California, Connecticut, Delaware, Georgia, Idaho, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Missouri, Montana, Nebraska, Nevada, New Jersey, New York, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Virginia, Washington, and West Virginia. Seven states allow unrestricted use of studded tires: Colorado, New Hampshire, North Carolina, Kentucky, New Mexico, Vermont and Wyoming.
Read more: What States Do Not Allow Studded Tires? | eHow.com
http://www.ehow.com/facts_5468627_states-not-allow-studded-tires.html#ixzz14qd8QBc0I got the info from that site