Just thought I'd suggest to you not to think that all tires of the same size are the same. Going to a larger (wider or whatever) size isn't necessarily going to give you more traction -- sometimes you can achieve more grip by staying with the original size and going to a higher-performance tire, instead of a K-Mart "special".

Of course, size does matter, too. For example, on my 240s (original size, 185/70-14), I use Michelin Pilot Exalto PE2's in 205/55-16 (speed rating, W) on Hydra wheels; my wife's car has the same tires in 205/55-15 on Virgo's. I picked them by studying magazine tire tests, as well as Tire Rack's tests. There are other good tires, as well. Just don't buy a fat but no-name tire because it's cheap and think you've enhanced your performance.

Anyway, just keep in mind that size isn't everything -- there are large sticky tires, and there are large slippier tires, too. You get what you pay for.

Good luck.