There's not much turbo lag in my Mazdaspeed6. Probably less than a 1/2-second. Its TMIC and other intake piping are all very close to the throttle body, so it doesn't take long to pressurize the system.

With the length of pipe used on the STS, there must be some amount of turbo lag. That's a lot of air volume between the turbo and the throttle body to bring up to pressure. But then again, maybe the turbo is big enough to react quickly.

I wonder what the turbo efficiency map looks like.
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1997 R50: VG33E/RE4R01A/TX10/3.7/R200A/ARB/4.636/H233B/ARB/4.636/321150R15