Just some pics of a body kit we installed a few months ago... Showing some work pics... It's a 2004 Mazda RX-8 with a BodyKits.org Invader Body Kit...
As you can tell from some of the pics, it was a damage car that a friend had that had been L-Boned if you want to call it that (got hit right in the fender at about 15 miles an hour).
Replaced with a Fiberglass replacement Fender and Invader Body Kit. Didn't install side skirts because the door had to be replaced but they wanted the kit and fender installed first. Had to remove rear security bar to install rear bumper, but other than that fitment was great with no need. Front bumper had a few small cracks but easily repaired with fiberglass and body filler. Body lines meshed excellently.
Sadly, the body shop ended up finding the frame was bent, and when the customer's dad took it to insurance to have a new estimate, they threatened higher insurance if the security bar wasn't put back on. Therefore, customer ended up having to buy all new factory parts and having them installed.
MORAL of the story - If you install something that makes your car not street legal, don't tell the insurance company...