http://www.mazdatrix.com/faq/port6p.htm

I just looked through this, and noticed that they're keeping the high speed valve functional.  For our use, that's not really the best way to go.  Pick up a copy of the 13B overhaul video that Bruce Turrentine produced, and you'll see a method to eliminate the valve, and smooth out the secondary flow with a type of epoxy.  I'm not real crazy about the thought of putting anything that could come loose in the port, but lots of people do it, and I haven't heard of it ever being a problem.   

Cheers,

Rusty