Some have advocated making radial cuts in the fender under the flare, bending out and bonding to the flare for strength. Personally, I would not do this if riveting the flares on and leaving the riveted look. My GT5 has factory blended flares and the fender is a crude cut (sharp edges and all) to mate with the inner seam of the flare. No issues with flex or cracking at the bond, however the fronts suffered paint cracking on top after I drove in a rainstorm and it then sat in the hot NV sun.
I have a photo of a GT5 during the cut process, but no software here to reduce it to post. I'll get it posted over the weekend.
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