I finally installed the improved upper grille block today. It looks quite good to be honest.
It has many advantages over the previous version. It features a dual-layer (coroplast + styrofoam) for better insulation. The styrofoam-coroplast add-on now allows the grille block to be "flush" with the hood which could improve the laminar flow upfront compared to the stock grille opening. It is also impermeable and easy to clean due to the carbon-fibre-style vinyl wrap.
I lent my camera to my brother so the pictures will have to wait.
Stay tuned !