Ok so I need help to figure out what I should do next here's my setup ,
Sr20det black top Turbo - gt2876r - walbro 255 - z32 maf stock 370 injectors bored to 550's so I'm told - 1.1 mm metal head gasket - arp head bolts - adjustable waste gate - boost gauge in car - aftermarket light weight pulleys - safc-1 not installed - car has redline performance pre tuned ecu, ecu is tuned for 740 injectors , z32 maf , and I believe 17 lbs of boost to make a rwhp of 450 . My question is , what should I do to the car , should I leave the pretuned ECU in the car and install a air fuel ratio gauge and the safc and upgrade my injectors to 740's like it said and then go have the safc and car tuned? Or should I buy a stock ecu, airfuel gauge and maybe upgrade to 550's and sale the safc and go get the car tuned and be done with it? As it sits right now , the car was tuned by turbo Dave in atl, at 17lbs at 300rwhp, and they had the fuel pressure regulator turned way Down so it wouldn't fluid the car out at high boost, since it has the pertuned ecu for 740's. I just bought the car and need help with what I should do to have a safe daily driving car, I figure just get 740's and install safc and have it dyno and the safc tuned and it would be fine , but my dad and his 240 buddy seem to think I might have problems if I keep putting money into the car without knowing what I should do . I know the pretuned ecu probley wont hit the number it says it will but I'm on a tight budget and need to get people who no about these cars to help me figure out what to do , I was told the car is running a bit rich cause they couldn't turn fuel down anymore but I haven't installed a air fuel ratio gauge yet so I dont no if its rich or just right or leaning out . Help plz

Your setup with those 550 injectors sounds like trouble for that setup.. Get the 740s, tune ecu by Enthalphy, and ditch that safc. I have a GT2871r .64 ar, 810 cc injectors, z32 maf, 1.1 mm HG, 256/256 cams, with Enthalphy Rom tune. I'm supposed to be somewhere from 300-350whp

Btw: I'm supposed to run at 18psi on 93 octane. Whoever tuned your ecu should've taken care of your afrs, but then again you did get it tuned for 550 injectors, re tune maybe?

Yeah I think im gonna get 740's and and just wire up the safc and go dyno the car and make sure its a safe tune with the air fuel ratio and stuff , since its a redline pretuned ecu I can't retune the ecu itself but after I put the new injectors I.can turn my.fuel pressure regulator back up and have the air fuel looked at when its dyno'd to make sure its safe and the car isn't running lean or rich , I just didn't mo anything about the eh but everwhere I've looked seems like the dude who tunes them is pretty good , so maybe it wil all work out , thx any other imput on what I should do next to the car would be apreciated to gain more power , what's the next.best turbo ? Since I have the gt2876r?

People usually go to the next level after they grow tired if the 28. That being the gt3071 for big power

Btw: call Martin from RS Enthalphy, this guy is awesome. I had problems with starting my car after it was all put together, I called him and he helped me in everything even performing diagnostics as to why it wasn't starting. He will tell you what you need to know. His customer service is also great, look up his website and call him up. His tunes are $400 for first time and $150 for a re tune.