There is a lack of available OEM sized tires suitable for my MINI JCW GP to use at Autox. I am running the original 225/35R18 Hankooks and would like to move to the Yokohama A052s, but no one knows when they will be available. I am considering moving to a 225/40R18 to expand my options. My question is will this adjustment to the sidewall impact my car's handling/performance? Any recommendations on suitable replacement tires would be appreciated. Right now I'm leaning toward the new Bridgestone Potenza RE-71RS.