t3 or t4

Not that mechanically minded so be kind. Just wondering how much work will b needed if one of these was purchased as in what else would i have to upgrade in the engine plus would there be much gain from of of those turbos? Turbocharger Kit

i found a good shop in amerika ho offers nice turbo's, im looking for a t3/t4 becouse i heared good things about them but there are many versions so wish one is fast spooling and gives me 275 to 300 wheel pk at save boost levels? Garrett T3/T04B S Trim - 125-300 HP Garrett T3/T04B V Trim...

I have read the stories about ihi, gt28rs and k04. But i never heard of somebody going t3/t4. This is a very cheap turbo and good for about 275 bhp. Is there a reason why this model is not so popular. The yanks do use is a lot and the stories sounds good.