wel generaly you check it for shaft play! in and out,up and down,youl probly get a small amount of movement,anyting more stay away.
seals gone the exhaust side would be quite oily.so just check that aswel,also try get a turbo with no cracks round the wastegate..its hard to come by a good ct9 doh! id say 90%of the ones i seen or took of cars had cracks or seals going an gone.