Well, If you have the air pump passages, the catalyst, what else do you need,... other than lean enough jetting and idle settings to get by the unburned HC test..?
Don't know about any comparisons to Hookers on our trucks,... the last Hookers I had were the adjustables on a 327... they worked GREAT 2500 to 8K rpm, and you really could feel differences when you changed primary or collector length.
The "press" on the TriYs is that they're good for street/torque applications, but everyone tends to change the whole system at once rather than just the manifolds/headers, so quantifying the contribution of the headers alone is problematical in the real world.
So, who knows for sure ? I don't. But , they're pretty, and they sound nice

{smoke}
