From what I have read and researched it should be OK as I also plan on + sizing to 245/45/18's as well from the stock OEM size.

 

For sure. Wears faster tho. Tires are always compromise between wear, noise, comfort, handling.

 

Why would a wider tire wear faster than a narrower tire, if both are exactly same product otherwise and are used exactly similarly? Is there any scientific evidence supporting this?

 

I think he was referring to the Michelin Premier Tire itself wearing faster as opposed to the sizing difference.

 

I think the Premier and Primacy Mxm4 have pretty similar tread wear warranties.

 

I found some Pirelli CintuRato P7 All-Season Radials 215/55R17 on Amazon for $109. Printed out the Amazon page and went to Discount Tire, who had the tire in stock for $290 each. They matched the Amazon price with no questions asked, plus allowed me to pay $68 for a 10-year warrant that if ANY of the tires were damaged such that it had to be replaced, and a new tire would be more than 2/32 inch different from the other tires, they will replace at no charge ALL four tires. This was a great deal and I have four other cars, which all will be running on Discount Tires from now on. And by the way, my 2011 GS350 has NEVER ran so smooth. These Pirellis are at least twice as quiet as the OEM tires. Absolutely fantastic.

 

The big concern probably isn't the extra 10mm in section width, but rather the extra 9mm in diameter. 235/45R18 is approximately 668.7mm in diameter. 245/45R18 would be 677.7mm. This'd raise your car's ride height by 4.5mm and increase your effective gearing by 1.3%, throwing your speedometer and odometer off commensurately.

The old rule I've heard was +/- 3%. 1.3% is obviously within that. It's just something to be aware of.