I live In the Phoenix arizona area and I have been looking for a miata tuner who works with megasquirt and an engine builder for the 1.8
anyone know anybody that does either?

 

UMS Tuning can do engine builds and can dynotune megasquirt but that is definitely not the preferred engine management there, especially the diy ones since so many people botch the installs. Most people will suggest asking your tuner then going from there to decide on an ECU.