JDM header

[Wayne]

Hey Guys...

Found a JDM style tubular exhaust header / manifold for sale.  Are
these anything worth trying to use?  Do they gain much power vs a
cast iron manifold or Hotshot headers?

And if they are worth messing with.....  how tough is it to fabricate
the lower pipe?  It's not included with this one.  Looks like the
tubes join into 2 outlets facing horizontally to the rear.

Thanks!

    -Wayne    '93 SE-R / '93 NK2k / '90 Miata