If you have the budget for a new one, go for a GT2860 IMHO
Be careful though with what you ask for as that is a very vague description still, id go for the 62 trim inlet wheel (47ind and 60exd) and then personally I would go for the .86 A/R exhaust housing, and sacrifice a bit of spool for reduced EGT, but you could use the 64 trim variant if spooling quickly is your main concern.
Let me know if you need putting in touch with a decent supplier.
Its vital to know what you are talking about when ordering a turbo.
Saying "t28" or "gt2860" is like saying "ford escort", without the specific details you dont know if its a 1.4 popular or a cosworth.