http://www.treadstoneperformance.com/prod_imgs/installation/ul/install-1.pdf If you will notice in the Turbonetics matrix chart, they only recommend a .81 A/R for the turbine housing. A "Q" trim turbine wheel, But look what HP they are saying what the .81 A/R is used for 1000 HP! A .96 A/R is good for 1200 HP.
I do not think Snowman is looking for a turbine housing of .81 or .96 right now that is good for 1000-1200 HP,just me thinking out loud.