How to identify a Big T28?

[BillDCat]

I've been in the market for a used Big T28. From what I understand these turbos use the same housings as a T25. So what I'm curious about is how I can tell that a turbo that I'm looking at is actually a Big T28 and not just another T25... i.e. I just don't want to get screwed in the deal. Also, it'd be nice to know the differences between makers... i.e. if it was a Forced Performance Big28 vs. other big T28s. Thanks in advance, guys.

 

[L2RTSiAWD]

The compressor Wheel blades will look different.

 

[DSMNightmare]

Yeah what he said. Also, if you buy it from a shop it should say so on the recipt