Well 215's would also be pushing the limit of what you can fit inside the stock fenderwells w/o modding anything (rolling, flaring, etc) to prevent rubbing. You also have to consider rolling diameter and what sizes are available that closely match the stock tire diameter. For example 205/45-16 is pretty close to stock size, but 215/45-16 is too big, and 215/40-16 is too small.