Those are actually a true fit for a YJ, and as far as a cj goes, they add approx. 2" of tire clearance to the rear of the front fender, & approx 2" of tire clearance to the front & rear of the rear opening, so in answer to your question: YES they do require cutting, to match their profile, they are not a direct fitment, or (as I have seen others do), mount the flares & paint the body overlap black, & it is virtually un-noticeable, also the front "roll" of the flare is more squared than the cj front "roll" of the factory fender.
I actually have a new unused set of these exact ones, that I will not be using, once I got them & saw the overlap, I decided if I was going to cut the fender to match, I'll just go with the TJ flare, because you pickup an additional 4" of tire clearance.
Drop me a pm with your email address if interested, & I can also take pics of it held up to my Scrambler so you can get a better idea of what I am talking about, also if you want them buy mine, they are brand new, & I'll sell them cheaper to you than amazon has them for just to get them out of the garage!
