Well, you are right in the fact that my statement was incorrect, and that O, P or Q trim refers to a turbine wheel, but they refer to full T4 turbine wheels, not T3 turbine wheels, which the turbos being discussed have. So, either way, something is goofy here.
I'm not positive, of-course, since I do not have the turbo here in front of me, but based on the ad, I am led to believe that the O-trim turbo is a full T4, but with a T3 flange, which is a common feature of MP turbos.
