Are the headlights on your Infiniti shining up in the sky or are they blinding people when you pass by them on the highway. The video above is a great tutorial on how to adjust you headlamp height settings.
According to the video description this method should be the same or similar for 2009, 2010, 2011, 2012, 2013, and 2014 G37 sedans, as well as the 2015 Q40, and maybe the newer Q50 sedans. The headlight design was very similar for those years.
You can also check out the other “headlight” posts on this blog that might help you in replacing your headlamps.