A k04-023 turbo from a 225bhp TT does fit with work, but it will be costly.
If you want abit more power and some nice torque then would recommend getting a K03s turbo of a later mk4 golf, these are a straight bolt on to your exsisting manifold, you can still run standard fmic, injectors. Would recommend up grading to a 3 inch downpipe, sports cat and a milltek cat back exhaust, a good panel filter, forge TIP, Forge 007p recirc valve.
This is what most people do and they get good results with a r-tech remap. Your better off discussing your requires with R-tech.