[3BarBoost]

So it was a thrust bearing failure (or defect) leading to a seal failure. Hmm, did you get a new wastegate, surge valve or vacuum lines in the deal? The axial play is one of those things MHI checks as part of the manufacturing process, since compressor to housing clearance is critical for turbo performance - so the bearing either wore out or got damaged after installation. Usually this is from a surge valve leak allowing turbo overspeed. Did the car perform normally (make good torque) before your cloud of smoke? It sounds like it.

The water cooling circuit for the turbo bearing is designed to allow siphon convection of the bearing housing after shut down, essentially preventing excess heat build-up same as a turbo timer. I would recommend against a turbo timer - but then would be accused of having some ulterior motive, so I won't say either way. But search through the threads and form your own opinion.