You should be able to max out a modified stock turbo with higher fuel pressure and just '04+/S1 or S2 injectors (depending on the car). If you go big aftermarket turbo then you should be good on fuel with those modifications although even those injectors may be a little too big depending on your power goals and how you plan to tune the car. It's always good to look into the future direction you're heading with a car and try to plan accordingly, but some things like injectors should be sized to your currently power levels and accept the fact you'll need to sell and upgrade them when you do add something like a bigger turbo. (There will be exceptions such as if you can reprogram the stock computer or run a stand-alone engine management system in which you can directly control fuel injector pulse-width and make some bigger injectors work better at lower power levels.) As you've demonstrated you might be able to make them work, but I've seen a lot of issues in trying to do so.
