That is rather odd. And I don't know what the specs are on these rotors or how much tolerance they might have for such a thing, but on many cars, if the groove is not deep they can cut the rotor a little thinner and it will work just fine. I would think that on such a fine car as we have that they might have thick enough rotors that this would be an option. But... I could be totally incorrect, too. Maybe something worth researching in case this comes up for someone else. (Unless someone knows for sure already). (someone?) (anyone?) lol.