the one on my 350z in that picture, has been cut up to fit the exhaust. I didnt hesitate to run them both knowing I would have to cut it. on my friends FD rx7, his exhaust and diffuser are not compatible either. He choose to use half inch aluminum spacers to lower his diffuser.
i would not expect someone making a diffuser to have to spend the time making sure it fits with every aftermarket exhaust. i care that it looks really good, thats what i want them to focus on. if it doesnt clear my exhaust, i will figure that out when i get there. its not hard to modify an exhaust or trim some CF.
I want this diffuser to look sick, i dont care if it fits all you guy's exhausts
