Koenigsegg Mods (tuning)

Are there currently any companies that have modded a Koenigsegg?
Like how the F430 got modded by Hamann

Not to my knowledge.

No, you can go to Koenigsegg and ask them to do anything you like. Though now they would tell you to get the CCX as it outperforms the CCR.

have a look on carbon fibre parts:
http://www.anamera.com/en/detail/car/16380/index.html?no_cache=1&ret=63