Technically the hub is the bit with the 4 threaded holes that spins round, the bearing carrier is what the hub is pressed into and the caliper carriers bolt to, but generally most people call the entire assembly the 'hub'.
Pretty much any if not all 4 stud VW/SEAT with 256+ brakes has the hub/bearing carrier you need, Passats in particular are a good source of cheap ones, but also found on Ibizas, Corrado, MK3s and even later Polos. Then you need the 280mm caliper & carrier, commonly known as 'G60' as thats what the Golf G60 got as std. But they're also fitted to several 4 stud VW/SEAT models, Corrado, higher spec Ibiza, even 5 stud MK3 GTI ones will work as long as you get the 280mm setup not 288mm.
You can even use 256 calipers on 280mm carriers, but you need to use 256mm pads and the slightly thinner carrier sometimes wont fit over a 280mm disc without using part worn pads or grinding a little off the slider pins.