Ive heard good things about "Arashi Turbo's" aswell. Im thinking about getting this one.
I contacted the the manufactuer about the turbo and they said that the exhaust housing is pratically a 10cm but they call it a 9cm. I also asked whats the lowest they would take on it and they said they would do $790 shipped.
http://www.ebay.com/itm/Turbocharger...0117ce&vxp=mtr