The subaru forums are broken down such as this, just an example:
*New England
Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont
*Midwest
Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Nebraska, Ohio, Wisconsin
*Mid Atlantic
Delaware, Maryland, Pennsylvania, Virginia, Washington DC, West Virginia
*North West
Idaho, Montana, Oregon, Washington
*Southwest
Arizona, Nevada, New Mexico, Texas
*Bay Area
San Francisco Bay Area and Northern CA
*Southern California
Los Angeles, Hollyweird, and any place with smog
*Southeast
Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee
*Tri-State
Connecticut , New Jersey, New York, Pennsylvania
*Rocky Mountains
Colorado, Utah, Wyoming
*Vancouver, British Columbia, Victoria
Isn't that Canada?
*Aussieland