(Oops, guess Sunny was typing faster than I was! Oh, well, here's my speech anyway):Once you know the wheel width, either from some helpful soul here or by measuring same (details upon request), go to a site like
http://www.tirerack.com and click on "specifications" for the brand and model of choice. The table that appears gives a lot of useful dimensions, including the approved wheel widths and tire outside diameters. Chose a size that fits your wheel width and an aspect ratio that gives an outside diameter within a percent or two of the stock tire. Any tire approved for your wheel width will clear fenders, struts, etc. with room to spare.Alternative approach: Hang around this thread until someone does all the work and comes up with an answer instead of my "How to"