It is also complete crap about the T34 with .48 tailing off at the top end.
Mine peaks at 330lb ft, and holds this past 6300rpm, with a .48 housing.
I have little lag, 150lbft at 1500rpm, my old T3.48 tailed off at 4500rpm big time, torque wise.
As a general rule, the housings do work as said, larger turbine will give more lag, but less oomph higher up nad be limited compared to a larger turbine, but by then maybe the compressor side will also be too small.
I always subscribe to the idea of why have a large laggy turbo if you dont need it, unless you don't mine the type r method of driving with loads of revs all the time.
Mine will keep up with city traffic comfortably from 1500rpm, and certainly by 2000rpm you cannot detect any noticeable lag.
tabetha