I have thought of buying the Stillen but I have read somewhere that the Stillen licence relocation kit does not fit the 2015 NISMO 370Z as the rod will not be long enough to clear the bumper. I ended up buying the Mower Axle relocation kit for 2015 NISMO 370Z. Their website is:
Carrera,Cayman,BMW,Tow Hook License Plate,John Deere,Kubota
Their craftmanship is superb and quality is really good. You can position the plate the way you want it. I chose to position it in such a way to not obstruct and for maximum airflow. Here are some pictures of mine mounted.