This larger turbo inlet elbow is strongly recommend for use with the M660, Pure 700, and M800 turbos. The factory inlet elbows are place an unnecessarily high restriction upon the inlet of the larger turbos, and they don't fit correctly to the inlet of the turbo, due to the larger, machined opening.
These inlets will allow the compressor inlet of the turbo to breathe properly.
Note: The original part was 3D printed aluminum. However, due to supply issues, the updated part is nylon.