Also, you can get an adaptor to put a t4 turbo on a t3 manifold. Dodge diesel guys get them all the time to put HX-40's on a stock manifolds.
I thought the prefered HX40 was the 16cm^2 T3 flanged one (both the regular and the "super").
I'm sure it's been done though (IIRC I've seen the adapters on fleabay).
