Originally Posted by brtecson
I was looking for the specs of the IHI turbo but couldn't find any. I'll look for it later.
I did a bit of looking around and found some quasi-relevant information.
Various iterations of the Mazda 323 GTX used either the IHI RHF5 VJ-20, VJ-21 or VJ-22 depending on year and trim.
Given that the RHF5 VJ-series of turbos are made by IHI, have ball bearing center sections, and have been previously used by Mazda, I'd say it's a decent bet that the Mazdaspeed Miata uses one as well.
*edit*
Hey, it looks like I'm right.
http://www.caranddriver.com/article....&page_number=3
Scroll down a bit and you'll see it says IHI RHF5.