245/45/18 all-around for coupe?

[emerthor1]

Wife just purchased 2004 coupe and the guy threw in a set of practically brand new Dunlop m3 snow tires. They are 245/45/18 and were only used for a few months last winter. He said they were great in the few times he traveled in snow. Anyway, I thought it was odd they were all the same size. I called our local Infiniti dealer and he said it wasn't that big a deal if I didn't mind some small handling differences. What do you all think about continuing to use these this winter?