Decision for new turbo to gain performance, GTX3071R?

[Racecobra]

Hi All!

I would like to change my turbo to gain performance. This means power and spooling response. A short summary of my current engine setup:
Engine: KA24DE(T)
Internals: Supertec pistons (9:1 compression), Pauter rods, ARP studs, cometic gasket
Valvetrain: crower 276/276 cams, modified springs.
Exhaust: Mazworks top mount exhaust manifold, 2,5'' turbo back exhaust system
Induction: Cosworth full front intercooler
Fuel: 625ccm injectors, AEM Regulator, fuel pump: 2xBosch(300l/h)
Ingition: AEM twinfire module with individual CDI pencil coils
ECU: Haltech E11v2
Turbo: T3/T4



At the moment I run ~370hp peak horsepower at 1,35bar (20psi) boost with 98RON fuel.
I would like to get better spooling response and 450hp peak. A rough calculation (AFR=12, BSFC=0,48) results in 45lb/min airflow.
I also tried to calculate the necessary boost, but I It's difficult because I have no idea about the volumetric efficiency of my engine. Due to the 276°/276° cams it should be quite good at high rpm. But on the other hand, my intake manifold and valve size is stock.
I think Garret GTX series could be the choice for me.
But I'm not sure regarding the compressor size, trim and turbine housing.
The turbo that come in to question from my point of view is theG TX3067R with 0.63AR turbine housing. What is your opinion?
Is it worth to invest into a GTX series (better spooling?) charger instead of GT?
Or should use an other turbo?
Any other engine modifications recommended?

For me, the spooling response/drivability is important.

Yes, lot of questions, but I have just sketchy knowledge about engines.

Best Regards form Austria,
Matthias