The GReddy or VAFC will definitely help with the mods you've got, but if you plan on taking the car further, you might as well look into the Hondata, Power FC, or AEM EMS. These three systems will not only allow you to extract the most power with what you've got, but they are an excellent foundation to build on for future upgrades (cams, boost, n2o, etc.).
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2005 s2000