Hello Wolfgang,
I don't play or mod 2015, because it doesn't support TrackIR for VR and modding to 2016 is a much bigger challenge. Also the 3D engine is different; 2014 has a better one. Also the support of Racing Wheels is better in 2014.
But why a 4 star rating while it is in the 2014 category?
Nice Job. If you want you can use all my textures from canada GP and put your really good sponsoring textures in the textures. I have not so much time at the moment to create new textures for tracks.