The rears 285/35's will definitely fit. Common size. Surprised you have a 285/30 to be honest, that's a weird size, and shorter than stock. 285/35's is what should of been put on.
The 255/40's, I don't don't know, that's a full inch taller, but should work. That'll be about identical to a 285/35. I have an S197, so I can't say for sure though. The 285/35 absolutely, the 255/40, should, but not certain.
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