I was quoted about £700 to have my GTSt (r33) turbo stripped, reconned and fitted with steel internals, Have a look round online, Phone people and see what they say...
One place I phoned sounded alright but I wasnt convinced, Another place I called described exactly what kind of turbo I had, And seemed to know every detail and said he had done quite a few before (he discussed the ceramic turbine and how it parts from the shaft ect) I felt quite confident with him and he was willing to guarantee the rebuilt turbo to a certain pressure (I forget now it was about 1 bar or just over) for a year with unlimited mileage...