first off, the central diff is relatively integrated with your tranny. It's pretty difficult to swap just the central diff as a stand alone thing. It's more complicated than the front or rear.
Second, putting on a fancier diff is not going to change much on an AWD car. The main diff of importance is the center one. The rear and front are mostly swapped out when you start making more power than the factory ones can hold. "would i be able to exit turns better and throw my cars rear end out of the turn like in evos and sti?" Uh, it'll make virtually zero difference. I have no idea why you are doing this mod. Most people who do it replace them because the stock ones broke.
if you want your rear end to swing out like a drift car, you bought the wrong car my friend. That's not going to get you around turns faster. It's just going to slow you down and burn more tires.
2015 STi: Still Stock
04 STi, 04 WRX: SOLD