|The old 525 was a fantastic option for those who did not want to go 5-bolt dp's, especially with todays prices of the SZ pipes that actually fit worth a damn.
Zooming in on the listing photos looks like turbine A/R is .63, so the same as the larger option on the previous 525, ideally the wheel tech refresh over 10-15 years makes up for the potential response loss vs .54 option.
As far as the A/R on the compressor housing, it was likely more about removing a restriction from the intake tract, im doubtful that it will actually impact boost response as much as the large increase might scare people into thinking. That could have been one of the keys to the increased max airflow potential as well. Think about gains from larger intake and intercooler piping, likely a similar effect.
Getting rid of cores is nice... when a stripped/snapped bolt in the turbine housing costs $40 ea off your core refund, and with the frequency with which they break....