The T04B and E compressors used are only slightly larger than the original compressor. Also, these turbos usually don't work so well in high boost applications when powerconsumption from the compressor increase. Take a look on the turbochargers used in F1 during the eighties, large turbines fitted in small turbinehouses to improve turbine efficiency and then a quite large compressor to that. Or why don't look on how a turbocharger looks on a diesel for a truck, large turbines which can power the compressor efficiently.
The basics behind matching is the same as for jet engines.
http://www.grc.nasa.gov/WWW/K-12/airplane/ctmatch.html