Turbo Recommendation for a 5S-FE Turbo Build Options

[Syaoran]

Hey guys so I'm starting to piece my build together and right now I'm going to be using the OE Manifold with some modifications made to it to allow for a bit better flow (ported and ceramic coated).

I purchased an e-bay cast-iron manifold adapter to use a t3/t4 hybrid turbo with an external 38mm wastegate along with it. Still have no turbo and haven't bought a wastegate either. I'm looking into purchasing an entry-level Tial wastegate. Anyways, here's the question.


Should I get a .50/.48 or a .50/.63?


I was recommended the first one by someone who tried it on one of his MR2s. He said it had a nice spool up (pretty quick) and that it wasn't too small and made decent power. Upon research, the .50/.48 seems to be labeled as a GT30-sized turbo. (which is a big turbo upgrade for many cars that come turbo from the factory like Mazdaspeed3 and Hyundai Genesis, so I'm guessing it's a decently-sized turbo)

The .50/.63 I am afraid that might not be necessary and will be detrimental to the spool-up time because of the much larger exhaust housing. Am I right or wrong on this?