Sorry, in small print under the site pics 'Sorry, this product is not available to residents of California.' Big gains are for turbo customers, smaller yet still significant gains at the top end of rpms for normally aspirated track 2.5 customers (and the amount depends on cams, compression, how high you spin it, etc).
DonovanS079 wrote:Are there any fitment issues if you’re using the AEM cold air intake as well as this manifold? Install thread?
From that pic above my assumption is no fitment with AEM intake. There are several threads at Miata.net on install details. Since we are in California, we don't see these in person.