Are there any retailers in your neighborhood that have a dyno and do tuning? Is there multiple shop?? Get a few days and take a look at the store, ask to observe them although they tune. Also the opening with the Blacktop inlet ports are somewhere around four to 5mm https://toyota4age05899.digitollblog.com/31971751/the-definitive-guide-to-blacktop-20v-4age