As said at least 100 times on this forum you want to take a look at the real specs, most are on tirerack. Those that are not can be found with a bit more research, usually on the tire manf site, side wall specs(same as listed specs like 205,215, etc) are randomly chosen it would seem as so many are very far off.
Look at section width, tread width, diameter and weight and read the reviews if published, tirerack ones comparing the different tires you are looking into are best.
For autocrossers, track enthusiasts, etc look into sites to see what is currently the best choices.
The widest tire you can fit under the car on a certain width wheel is not always the best choice, you want a little bit of sidewalls stretch for best feedback and control if your goal is the best grip and speed, if just into looks, do as you wish as long as you know you would more than likely give up some real performance.
Have a great 4th of July
Rick