what measurements could I take to determine what it is, or is it the shape of the compressore wheel etc.

Correct me if Im wrong please.
The T3, T34/35 T4 all use the same bearing core and the only difference is the housing sizes and compressor/impellor wheels. Thus as anything I buy is going to need a rebuild should I just put a t34/t4 front on this turbo and be done with it. or should I match the exhaust size or at least .48 size rather than the .4 or .42 it may be. or just posrt it back to the seller and demand my cash back!!

Hope thats self explanatory.
any ideas,

thanks again for your input.
Cheers,

Justin P