The width of the nose 50mm behind the tip is too large, it is set to 140mm in 2015. See my drawings on the second page of this thread or the pictures of the 2015 Marussia/Manor car( http://www.f1technical.net/forum/viewto ... 12&t=20798 ).
The last posts here are about if it is possible to smooth the volume next to the tip with a panel that does not count as a part of the crash structure. But as scarbs pointed out this will probably not happen if it makes the airflow worse around the nose.