hey adrian,
I have personally done 4 of these turbos with all awsome results
there are many ways to do the mod
just bolt on the housing gives u more top end but a bit more lag (but can be regained by porting and matching the manifold).
you can high flow the compressor at the same time keeping the ceramic wheel just increasing the compressor wheel and matching the housing. Have seen 230 to 250 kw out of this type.
or put a steel wheel in a vg30 turbo this is the way to go 270kw plus and will last foreva but is roughly 1500 bux u keep same lag and awsome mid range and top end.
We did quite alot of development on this mod and reducing or eliminating surge which u might get in doing this but it was minimal
If u want to know more about what ive done and ive got contacts on the machining a mate does it for ATS and i also know Bill from ATS so i get good prices on it all please call me or pm me im happy to help ya
P.S. the housing it self is very hard to find usually u will get a complete stuffed vg30 turbo for around $100 if u can find one and u need a ball bearing one the non ball bearing one does not fit, you can tell by looking at the back of the front compressor housing.
mike
0416 085 323