I did a somewhat lengthy post some months ago about the basic principles on how a performance header works. Based on the info and numbers gathered in that article I started looking for different alternatives that will fit my needs:

- 2" primaries or as close as possible
- 2.5"-3" out of the collector
- At least one O2 bung
- Cheap..

The RB header would be a safe bet and a quality product.
The ultra expensive fuji racing header or Maxim works would also be nice but very expensive.
Also all these headers have kind of small diameter pipes and only 2"-2.25" end pipe diameter.

As far as I can tell there are no Miata headers out there that has 2" primaries other than going custom or have stahlheaders.com make me one of their Miata 4-1 headers with 2" primaries and a 2.5 or 3" collector. Either way expensive. I might consider it later.

I have read some reviews on m.net about the (once) $99 Racland header. SS materials, 4-2-1 design and they even managed to pair the correct runners for the primay collectors :).
I got mine for $139 of eBoy.

So lets take a look at this "quality" product.
Some measurements, ( NB version):


Flange and dump od 60mm / 2.3"
Secondary od 48 mm  1 5/6"
Primary od 42 mm. 1 5/8"
Primary length 450 mm  17.7"
Secondary lenght 410mm 16.15"
Dp 280 mm  11"

Shiny stuff. Bling is enabled.
 

The flange is thick and has a machined even finish. Bolt holes are a bit larger than OEM (compared to a 99 Euro-spec header).  Ports are rough and uneven.  Looks like they just jammed a oversized dremel down there.


Some numbers on a sticker



The welds and craftmanship looks OK at first glance. Nice TIG welds and "stacks of dimes"


..but if you look a bit closer you can see some strange stuff going on where the pipes are welded together:


They use slip joint instead of butted welds on the runners.


Not good:


Collectors look ok from the outside:


But not so good from the inside. Lots of adges making restrictions and turbulence.


The same goes for the runners as seen from the flange:


The fitment down the transmission tunnel was cramped and needed som BFH action to fit without rubbing:



Chrome won't get you home:


Summary:  You get what you pay for.