Garrett AiResearch T03 Turbo (from VL Calai Turbo) - has a little bit of shaft play.
$150 ono
I Tried to find out a bit more about the turbo - its a bush bearing turbo, dont know how easy or hard it is to fit to an Rb25, should be cheap to rebuild though....In my limited experience I think even though its an old turbo would be a good cheap power upgrade for an RB25....