Maybe someone who has access to FB, can shoot a suggestion over to the vendor and ask if they could take the two far ends/corners, as it relates to the face edge, or front of the IC, to angle those corners in a lil bit, and/or make those ends follow the curvature of the OEM bumper.
Perhaps by doing so, BEFORE THEY GO TO FINAL PRODUCTION, that the lower grille can possibly still be retained.
Judging by the pics, that doesn't seem like to unreasonable of a request, as it appears the amount necessary to trim/angle/curve down, appears minimal at best, in relation to the overall size of the IC itself.