ok thanks
what you can drive at maximum performance with this turbocharger
It really depends on all of the other modifications and the supporting hardware, ecu calibration, etc.
The limitation is fuel in the Golf R. You can use RS4 injectors and an intank fuel pump and get up to 460-480'ish depending on what lambda you are comfortable with.
At 460bhp you will see .83-.86 lambda, timing advance of around 6-9 degrees. If you want to be more aggressive (dangerous to longevity) you can push it a bit further.
Turbo is good for just about whatever you throw at it unless you want to fuel with meth injection, higher than 130bar high pressure fuel or auxiliary injectors.
We have tested a GTX3071r on a Golf R at .88 lamba, injectors similar in size to the RS4's at 150bar high pressure fuel with a timing advance around 6 and have achieved 550bhp. That's way more aggressive than I would ever run my car or recommend to a client though.