here are some specs
HKS GT2835 - 380/400/410 PS Output
COMPRESSOR:
-Wheel- 48/52/56 Trims -
49.3/51.2/53.1 inducers / 71.1 Major
-Housing- 70 Inlet / 50 Outlet - 0.50 A/R
TURBINE:
-Wheel- 84 Trim - 56.5 Major / 51.8 Exducer
-Housing- GT25 inlet / Outlet spec:
Internal GT28; 0.64, 0.86 A/R
External GT30; 0.61, 0.73, 0.87, 1.01, 1.12 A/R
HKS GT2530 - 320 PS Output
COMPRESSOR:
-Wheel- 63 Trim - 47.7 Inducer / 60.1 Major
-Housing- 60 Inlet / 50 Outlet - 0.60 A/R
TURBINE:
-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer
-Housing- GT25/T3 inlets / Internal GT25/Skyline Type oulets - 0.64 A/R
http://www.hksusa.com/products/?id=711
that website has lot's of valuable HKS info