Quoting GSTwithPSI:
What are you power goals for the car, and how do you want it to make that power? That's the most important question your should ask yourself when selecting a turbo.
Most turbos T3 flanged are larger slow spooling turbos. You'll need to do extra work via tuning, or set up your car correctly to get these larger turbos to spool quickly. Typically, the DSM flanged turbos are what people use for quick spooling street turbos. In the grand scheme, the 50 trim is probably one of the quicker spooling T3 turbos out there.
If money is no object, a ball bering turbo is what you want. The FP HTA GT3076R is a sweet T3 flanged turbo, and could be made to spool quickly. Or, you could also just replace your junk Ebay turbo with a better quality 50 trim (Garrett, Turbonetics, whatever), and see better spool. On the journal bearing side of the house, you could go with an HX35, a Borg S366, or maybe even a T3 flanged 20G if you can find one.
If I were you, I swap back to a DSM flanged manifold, which gives you a wider range of quick spooling turbos that you'll actually be able to find new and used. You'll have the E316G, 20G, FP Green & Red, FP3052...The list goes on.
I can speak to this. I've got a T3/T04 Garrett frankenstein and even with porting, an FP mani, and 3" exhaust, my boost threshold is around 4k. Mind you, it kicks like a mule when it gets there, but if you want to run, you've got to keep those revs up.
