No I have not had experience with the CF ones, but man, for that price, you could buy the fiberglass ones from Classic Datsun and have them covered in CF. And they weigh 30 lbs too from MSAs ad!! Shipping must be a biotch.
As for cutting, guys have done it both ways, but it really depends on what your tires and wheels will do under the car and how wide you are going--if your tire & wheel combo hits the fenders now, you have to cut, but if not, then don't worry about cutting anything. They attach with rivets or nuts & bolts. That said, do a search and you should find a thread by ON3GO, I believe, where all of that was answered.
Davy