First, let me premise this with I am a novice at bodywork.
Now, this was not fun. I got these extensions in a bulk buy from a friend and since I am cheap I was going to use them.
I had shorten the extensions and then hack a wedge out to get to follow the quarter panel bodyline. 2 hrs later, voila, an extension that fits. I will finish up the gaps with my welder and get it prepped properly for paint later, but yeah...ugh.