What to do with my turbo ??

[CharlesRHD]

Hi, i am new to the RX7 world. I come from the Miata scene. I recently bought a 1991 JDM/RHD RX7 equipped with a 13B Turbo II. I was told that there was some issues with the Turbo. The issues is that when accelerating the boost will go from 0.5bore and then drop to 0.3bore. I was also told that the previous owner disassembled the turbo to find out that there was a good shaft play. I would like to replace that malfunctioning Turbo but my question is, which turbo do i need to get, what is the exact '' name '' of the one that i currently have in my car which is the stock one. Or should go for a rebuilt ?

Thanks a lot !