I've been considering this for some time and I figure the whole belief of you must go with 18/19 (f/r) is not entirely a "golden" rule. I'm also beginning to believe the overall diameter, at least on non SRT models (since I don't have one) isn't as much a concern as we are led to believe. If it were, why would the manual reco going with 225/40 VR18's all around in the winter?

Sure the wider tire is going to be better for handling in non winter weather climates on both dry and wet when you are more prone to be a bit more aggressive etc., but in reality I'm thinking (and very well could be wrong) outside of that aspect it boils down to "cosmetics" and the reason it is difficult to find anyone at tire rack, dealers, or retail shops to ever agree with you is they only go with what is standard, recommended by the manufacturer and where the almighty dollar is. Again, I point to the fact that it is reco'd that you go with the same tire size all around in the winter.

Using 1010tires.com I found I could go with a 255/45/17 or a 222/45/18 with minimal impact (outside of width).

So it really boils down to how much research you are willing to do and how "experimental" you are. Here is an article I found that briefly talks about Germany's ADAC regulatory body on the subject of wide vs narrow. http://www.motorauthority.com/are-wi...an-narrow.html