My other car is a MINI!!!!
The ebay link is a cheap chinese copy, I'd avoid that mate.
The ko3s you're looking for is a ko3-052, 053, or 058, all are essentially the same. they will come fitted to AUM and AUQ engines mainly. these are fitted to y2000 onwards(Typically) mk4 golf GTI's, leon cupras, octavia VRS, 180bhp TT's, facelift A3's, and a few others.
On a ko3S AGU, unless you're really pushing it to the absolute limit, the stock injectors will cope fine at around 230bhp satage 2 level.
People HAVE pushed the turbos further, with uprated actuators, and used a VR6 MAF and Saab injectors, but for the effort involved, you'd be better off going down the k04 route at that point.
All ko3S will be a direct bolt on fit to your car, you need the silicon TIP, or a ko3S TIP, and new crush washers for the oil and water lines, as well as an oil drain gasket and turbo / downpipe gaskets.