For add even a bit more detail: I used the ejector pin marks on the fender extender as guide where to drill the holes. On the picture with the bottom side of the fender extender you can see three in total, two more to the side, and one in the middle. The one in the middle would have ended up straight through the double-sided tape on the other side, so I opted not to use it. Instead, I drilled a hole in the two ejector pin marks on each side. Then, at the same distance towards the edge of the fender extender, I drilled a third hole in the middle, just a bit higher than the middle ejector pin mark. In such, all holes were at even distance from the edge.