If you are looking to keep the factory fuel rail setup then you will need to get factory injectors reworked, I dont think their is an after market one available.
You can get a different fuel rail setup and use top feed injectors. Ford ones should work fine if your fuel rail is made for them.
You cant judge how much injector you need by how much boost you are going to run. It depends on how much power you are going to be making.
The other thing you are going to need is a fuel management system, AEM would be your ideal unit however a vec 2 can do the job also.