Turbo problem diagnosis

[Benzsc1]

Guys as some of you may know I am looking to build a D24T with IC and now have three turbos to ch0osse from two are the AIRresearch Turb's that I asume come as standard on a D24T the other is a Garrett AR48 which I understand is the Turb's of choice used on the later VW LT High Torque engines although that is not 100% as i need to confirm it.

I am wondering how I can check to see if they are any good one of the AIRresearch blowers has play and feels a bit like its catching on what I call aluminium mould!!! The other AIRresearch spins freely and has no play in the shaft the Garrett spins freely but has some play in the shaft TBH I have always worked on N/A cars and even TD's have not been my forte but I need to start somewhere I would even be up for re-building a turbo If i knew what I needed bothparts and toold wise.

Any help would be appreciated

Si