They aren't so much about gains, but about improving sound and reducing rasp. Gains are a bonus.

Gotcha, just seems that people talk about gains more often than anything, and there is just no real proof out there. Id love to see some cuz then it would justify buying them... And of course i mean gains in comparison to HFC's, not gains over stock cats... Of course there will be gains over stock cats.

Yeah, they help improve the sound, which honestly, I can see that it does. It's the same as the HKS or ARK exhausts, just with the Hemholtz resonators in the front pipes instead of the axelbacks.