I havent heard thta much complaints about them, but if you have other options.. than they might be better... if that makes since. I know a guy who got a gude performance head package with the ported head, and TB. On his Escort GT 1.8 dohc and he dynoed @ aroudn 135hp @ the wheels from the original 115hp to the wheels that motor puts out..thats a decent gain for the price.