Did this require drilling? I haven't been out to look at mine. Seems the most secure.
No drilling of the hood is required. As BarnyardsTDI indicated, you can slip the zip tie under the gap in the sheet metal. You'll see it right away when you look under the hood. For the three tabs I wanted to fix, I positioned my 2 holes in the insulation to match the two sides of the sheet metal where each tie is looped to the hood.
I did use a drill to make the small holes in the insulation, but you don't have to drill the hood. At least that's true for the 3 tabs I wanted to fix. To me the sheet metal of the hood looked a bit different at the front of the car, but I didn't have any sagging at the front. I like the new insulation much better, but this same fix might have also solved the issue with the old insulation.
Edit: I just saw a closeup of the photo from BranyardsTDI and he has ties on almost every tab, even at the front. So it looks like it could also work the same at the front.
