I do not own the Negi, but I got to look at it for a day or so. I remember that his mainline is the Kb1-f5 variation, where Kozul and Jankovic recommend Qc5. So, the moves after the initial Kozul position are
11. Kb1 Qb6 12. Nxc6 Bxc6 13. f5
I think Negis mainline is 13. ... b4 now, where he also adresses Marins proposal. I didn't properly checked it, but a friend of mine did and he believes that Negis analysis on that can be improved fairly easily. Food for thought?
But my interest lies in the comparison to Kozul and indeed, they meet in a sideline after
13. ... Qc5 14. Bd3 h5 15. fe fe 16. Rhf1 (Kozul looked at e5!? mainly) Bg7 and now Negi proposes 17. Ne2 which only got an "unclear" sign by K&J. He then follows a correspondence game but I think there were not much else analysis. For me, even without checking this does seem like a proper way for White and Black. Negi can claim a typical advantage, while Kozul and Jankovic seem to be happy to play Black in another typical, unclear Kozul variation. So not a big upset here!
I hope that this answered your question