Thats a great Idea on using bigger injectors in the back. I am using stock twin turbo injectors now from the stock NA injectors. Right now it runs rich on the bottom end but my O2 sensors when out on me as well and havent been able to get some time to change them out. I am assuming that is why it is really rich on the bottom end right now. What size would you think the rears need. I do believe they are 370cc if im not mistaken