I've done a fair bit of reading.

I know the turbine passages are 0.6A/R
I know they use 57mm major axis compressor wheels
I know all models except the JDM 276BHP models use 51mm turbine wheels.
I know JDM 276BHP models use 50mm turbine wheels
I know JDM 276BHP models use the zero clearance plastic compressor housing.

Does anyone have the details of the compressor and turbine minor dimensions or trim ratios. I'm sure I've seen them before but can't for the life of me find them again!
I think I read somewhere online the compressor is also 0.6A/R but can't be sure.

 

Do you have the paper that details the sequential twins that the Mazda guys wrote up? I believe it was published by the SAE?

 

ooo, yes that might have been it! I think I have the paper for the earlier models.

I have seen the document for the 13B-REW sequential system. Not sure if its still in my data library.