The correct size for the rear is 255 35 18. The ones you have are 1" larger in diameter, which is pretty significant. Not sure if that would contribute to the inner tire wear you have on the front, but the stock lower control arm (LCA) bushings on our cars are soft and are well known for causing that kind of wear. Definitely get them to replace the rears with the correct size, and as far is I know the only way to correct the inner tire wear problem is to replace the LCA bushings with aftermarket ones (like the ones FIGS Engineering sells. I bought them and love them!).