Check the vacuum lines and VNT actuator first, they are much cheaper. Take a look at this article http://www.myturbodiesel.com/1000q/a4/VNT-wastegate-adjust.htm and isolate the problem.
If you isolate the problem to sticky vanes and don't feel like taking it apart, then you can buy a new turbo. No point in replacing the whole turbo if it only needs a new actuator.
RE: gra900, get error codes first. If EGR-N75 swap fixes it, you found the problem. Also check all vac lines, very common problem. See the limp mode FAQ article, it has more troubleshooting steps.
If you isolate the problem to sticky vanes and don't feel like taking it apart, then you can buy a new turbo. No point in replacing the whole turbo if it only needs a new actuator.
RE: gra900, get error codes first. If EGR-N75 swap fixes it, you found the problem. Also check all vac lines, very common problem. See the limp mode FAQ article, it has more troubleshooting steps.
