I would contact the manufacturer or the retailer. I was trying to go from 20" to 19" and I was told the 19's would not fit with the factory offset. Correct me if I'm wrong, but isn't +40 the factory offset for the fronts?
However, I was able to find 19" wheels that cleared the 2018 Red Sport brakes with the factory offset. So, I believe it depends on the wheel design. I think I've seen those wheels on the fitment industries' website. I think they even have a Q60 with 18's. Good luck.