1990 300D advice

[calebc3]

Got a tip on a 1990 300D with the 2.5 turbo for sale. Seller claims that the bearings are shot on the turbo and it needs a rebuild. From searching it seems like people are pretty fond of this car. Also from searching I couldn't find any problems specific to the bearings on the turbo but found some info on some vacuum related stuff and the transducers that can affect turbo performance. Being more familiar with non turbo 123 vehicles, what are some tips if i decide to look at the vehicle? If the bearings are shot should the vehicle still be able to drive, just a little sluggish? What is a reasonable price to have this turbo rebuilt if needed?
Thanks.