The offset of the wheel determines how wide of a wheel will fit, the width of the wheel mixed with personal preference of overall comfort vs. handling determines how wide of a tire to use. It's all a matter of how much you are willing to compensate between comfort and handling to make something fit, and I guess how much sheet metal you aren't afraid to modify.
The white car in my sig is a 4 door and I had to beat the outline of the rear doors inside the wheel well flat just get 205/50 r15 tires on a +38mm offset wheel to not rub on it during hard cornering. Then you have guys like this with a purpose built 4 door Protege race car not really having to modify anything to fit 10" wide front wheels with 235 or 245 series tires and 8" or 9" wide rear wheels.
http://www.clubprotege.com/forum/showth ... post639004
I tell you what, I wouldn't want to drive around these New England roads on his suspension setup though.