The Mazdaspeed 2.3L turbo engine with direct fuel injection and purposeful use of cylinder cooling to prevent knock has a very advanced and sophisticated electronic engine management system. Add to the mix the efficient but reatively small K04 turbo with a very small and heat vulnerable 5mm center shaft. This is a recipe for disaster with manual boost controllers or stand alone electronic ones that are not integrated into the entire engine management system. Boost is safest when managed based on engine load and rpm in a system that carefully adjusts boost and fuel mixture richness in a pretty complex algorithm.
Stated shorter: You need a comprehensive tune that remaps the entire ECU, rather than a boost controller, if you intend to safely raise boost above 15 psi on this engine. You will also need to replace the high pressure fuel pump or upgrade irs internals with a bigger piston to increase fuel volume and pressure, or you will soon run into lean outs under load that exceed the ability of your engine management system to correct. Then you go zoom, zoom, boom
I recommend one of these three, beginning with the plug and play Hypertech. I run it with the mods listed below. With careful mod selection it will just about max out the stock turbo on premium pump gas, giving you 18-19 psi when safe, dialing it back approaching 6k rpm, while richening fuel at that point and dramatically increasing timing at high rpm and high engine load. You can see 300 whp this way.
You cannot safely see those power levels for very long with your approach and will likely conflict with other engine management efforts of the ECU. You will either have boost cut or fuel cut protocols jump in, or if bypassed, blow the engine.
If you plan to run a bigger turbo or change manifolds or engine internals, you will need the customizable Cobb Access Port (AP) or Versatune to develop custom tunes from their stock map collections for the mods and fuel you are using.
There is another board called Mazdaspeed Forums where you can obtain detailed and very accurate information from highly skilled amateurs devoted to this engine. There you will find detail on why a stand alone electronic tuner is an invitation to quick disaster on this engine. There you can learn how to make real power without breaking your wallet or destroying your engine.
I could tell you how to "plumb" your EBC, but I would be blamed wben you blow your engine.
