Let me rephrase my original question.

In my eyes, if these tweaked manifolds provide upwards of say, 15-20HP you would think it would be talked about quite often on the forums. And by quite often I mean more than not at all. I haven't seen any mention of these things since I've been a member and you have to go way back to find posts about it. Especially considering the total cost would be around $700, which is well within the realm of the big 3 mods ($800 NW dual, $800 for 185 pulley, $500 for tune).

I'm just confused why this mod isn't talked about more. Where are the numbers!