Help with tune/ecu questions rb25

[camo240]

I have a rb25 series 2 and I'm running a different turbo that came with my swap. It's a custom turbo. The guy said its just a little bigger than a gt2871r. Garrett won't email me back with specs yet. I'm also using the cxracing top/forward turbo mount manifold. Now I was told I need a power fc bc the stock ecu can't handle it? I'm not planning on going over 12-14 psi if I can still use stock ecu. I don't have motor in yet bc I'm waiting on my harness and need a one piece drive shaft and clutch and flywheel. So I want to get it all first before I swap it in. So my ?? Will I be ok running a stock ecu with this turbo and mani? If so what is my boost limit without tune? If I can't then best choice to run my car? Don't have a lot of cash but may be able to afford like 800-1000 when I sell my rb20 parts. I plan on doing a Freddy intake and injectors later down the road and want to run more boost later on. So what do you recommend? If someone has time to bs about this I will pm u my number. Any help is appreciated!!! I searched and so much flaming I can't get a real answer for what I'm running. Thanks