After scouring the webs for info before my purchase, I determined that if you are utilizing the stock suspension, you are OK with either.  I did read a post of a guy on that had stock susp that had minor rubbing at full lock with the 205/45's.  Most with them say nothing.  The 45 route offers more choices, softer ride, but has a slightly narrower contact patch.  The 215/40 route has less choices, larger patch and zero rubbing reports on stock susp that I could find.