That turbo is a very strange spec. It has a huge compressor and a tiny weeny turbine wheel.
This is the problem. Theres a small number of companies that have worked specifically on the 1.8T, and have figured out what works and produces results, and what doesnt work. Anyone else without that expertise is just guessing.
If your going to get a hybridised turbo, you really want to be dealing with one of the firms that knows what they're doing. Or be able to provide an EXACT spec that you want built.
Beachbuggy put a lot of effort in and produces some nice products for instance. Frankenturbo also put some effort in, but their reputation has been a bit iffy. Certainly better than buying random unknown crap off ebay though. The problem is all of these options cost, because doing it right costs.
If your wanting a cheap reliable hybrid option, then i would source a factory turbo from an 8L S3 or TT225. Part numbers are K04-020, K04-022 and K04-023. Then have a GOOD turbo shop machine the A4 K03 turbine housing to accept the S3 turbine wheel.