Ill call a big BS on that. They just don't like it. Some like em, some don't on the basis that the nylon erodes where the double roller link ends ride. that nylon 'gets into motor'....past the oil filter? Ill call BS on that too. Its purpose is to steady the timing, it doesnt prevent the stretch. I think its a great addition to a build and has been used on millions of cars successfully. Its like politics here. very hard to swing someone off their beliefs on it.