I think Jap turbos are some of the best quality turbos out there. They make really good power for there size. They just don't hve the same bang for buck that the old school American turbos have. You can pickup a T3/T4 turbo for around 550 new. Most HKS, Apex turbos start at over 1K and go up from there.
As for the VG30 turbo there was never any VG30DET powered cars in the US. Unless you are talking about the VG30ET from the older 300zx's. The only other turbo VG we got was the twin turbo 300zx. But from what you have said I think my money would be better invested in a good FMIC.