ok, correction, there are a few places that will rebuild bearing turbos. however, it is an extreemely costly enterprise and is not commonplace. ie up to $1700 for a rebuilt core (one quote i got). compare to GT28 (360hp) garrett brand new for $2600.
if the turbo has got life in it, great, theyre a good unit for specific application. however, future potential is severly hampered by non interchangeability of compressor/turbine housings with other garrett models, and the price/availability of rebuild is prohibitively expensive.