Extrude honing stock exhaust manifolds

I would like to create tubular manifolds on my Z, but don't see it happening anytime soon (need tools). So, i've been considering extrude honing. Perhaps a porting of the stock turbo manifolds + extrude hone would yield some mild gains? I searched on the forum, and found an old thread, but it was more about someone trying to sell the process, not what gains were there. Anyone know if this might be worth the money on stock manifolds, or should i just save up for the tools i need to create tubular manifolds? And if someone has happened to have done this before, any decent gains?

Sorry, not trying to make a thread about "how much power will i make!?", but i'm more curious if its worth the money. I mean, if its $200-400 for both manifolds and it yields 20Hp then it might be worth the money, but if its 5hp.. then not really.