From what I recall again, the reason Porsche did that is because the VTG can supposedly only tolerate being pushed to 1.2 bars for a brief period of time before it produces too much heat. Don't quote me on that though.

 

that's why you need an exhaust to help lower the temps.
but seriously, since overboost is only available between 2k and 4k rpm, how long does the TT spend between 4k and 6k rpm? I would say very few seconds even in 5th, can these extra seconds generate that much heat? I don't really buy it. I think it is just a way to detune the TT in preparation for the S/GT2.

 

Related question: When do you guys think the X50 version of 997tt will be released? Probably after the GT2 is my guess.

 

I have never tracked any car, but would you not be way past the shift point after 10 secs in any gear? Seems like it would stay in overboost in each gear all the way to 6th as long as you had your foot in it. If you have experienced more than 10 sec of overboost in 6th, I hope you are on a deserted runway and not the back straight.
There's a pretty good explanation on pp 28-29 of the sales brochure.

 

I thought I heard or read that in addition to a small HP bump, the S may be available with DSG?

 

Problem with the 997 turbo S is that the 998 turbo will be around the corner when it becomes available.