I'm well aware of that, Swacer

But my NX doesn't make a typical high RPM startup, sound. It also sounds like that, plus the turbo winding and spinning. I was wondering if the NX does that to sort of "warm up" the turbo as well.
If I can later, I'll run out there and take a video to show what I'm talking about. It's sort of difficult to explain.

 

I usually let the RPM drop to 1k then off I go regardless of outside temp. So I use a bit ounces more gas, big whoop. My engine, transmission and engine mounts will thank me when I spare them from the shift shock putting it into drive from park without letting the RPM drop.

 

The initial start up "hammering" sound is a valve designed to get the Catalytic Converter hot quickly.
Once the cat sensors report enough heat, the valve changes and the clatter goes away.