The 2018 factory front "under spoiler" is different from the 2017's - it comes to a more "square" point on both of the corners. Personally, I like the flow of the 2017 style better.
To guarantee fitment, I'd look up a dealer that sells them and ask their service dept. if they have instructions or if you can talk to a tech. The shape is slightly different but the actual attachment points might be the exact same.