@raymond: about the slit in the above picture I do not know if we are seeing a slit on the airbox or if it is just the engine cover bending and not being in line with the adjacent bodywork.
High pressure on the inside in that zone maybe?
about the nose inlet: if you give the flow a separate stagnation point the boundary layer thickess starts from zero at stagnation. So with a separate leding edge above the inlet you have a new boundary layer starting form there, and not a boundary layer which has suffered some loss because tha flow has decelerated on a ferreari like bump and then accelerated again.
The advantage of a clean boundary layer on top of the nose should be minimal, but in the end why not? It comes for free.
By removing the cooling inelt in the nose you could also get a minimal increase in flow under the nose: almost negligible, but again, why not?