997 Turbo S, 997 GT2 and Tuning the 997tt
Information from a reliable source is that the VV turbos will not be as easy to tune as (certainly I) assumed. The VVT turbos which KKK have developed with Porsche are basically the biggest they have made to date and the thermal limits are critical. Whilst bolting a K24 compressor wheel on the compressor side will be an obvious next stage for a Tuner, the ultimate level of power will be determined by the maximum flow the hot side can produce. There are no "bolt on" hot sides which Tuners can play with (unlike currently where say a K24/26/27 etc can be mixed and matched) and it is unlikely that KKK will or can (because of technical issues) develop bigger units to satisfy the limited demand of the Tuners. The other issue is the fact that the VVTs have no wastegates, the boost is controlled solely by the ECU altering the pitch of the vanes, this introduces all sorts of problems when trying to extract more power.
Expect a maximum of 550hp From the current turbos (with K24 compressor)but with superb area under the curve.
Expect KKK to develop one more VVT for the upcoming Turbo S which should make 510 to 520hp. Bets are that there will NOT be a GT2 because unlike the 996tt it is not a simple matter to do away with the four wheel drive system and it is unlikely that Porsche will invest in making a bespoke 2WD system baring in mind the lacklustre performance (in sales terms) of the old GT2.
DSG not until 2009 ?
Expect a maximum of 550hp From the current turbos (with K24 compressor)but with superb area under the curve.
Expect KKK to develop one more VVT for the upcoming Turbo S which should make 510 to 520hp. Bets are that there will NOT be a GT2 because unlike the 996tt it is not a simple matter to do away with the four wheel drive system and it is unlikely that Porsche will invest in making a bespoke 2WD system baring in mind the lacklustre performance (in sales terms) of the old GT2.
DSG not until 2009 ?
). And if grandma is driving with TipS, she has the advantage over the 996TT from pre-boosting the turbo's during gear change in the torque converter. No doubt the tuning market will be challenged by the 997TT with all its computer/electronic advances and its technical sophistication, requiring more complicated (and more expensive) mods., and increasing the potential for c--- mods., both unreliable and underperforming. But I share RC's guarded optimism that some aftermarket chip tuning/airbox/exhaust mods. will be available, and since the VTG's have high torque at low revs., in a paradoxical sense, just subtle changes in engine programming (like re-setting the overboost function to come on earlier/at higher boost/for longer) with appropriate air intake and outflow increase, can make the car more powerful and faster-I bet this is what the "S" will have-although it would also be cool if the "S" had a different VTG than the base TT's, implying that it could potentially handle higher boost pressure and thus higher temperatures. Since hyperthermia will be the limiting factor in reliability (because higher fuel/air/exhaust temps. will via feedback inhibition to the ECU limit maximal power output), the more readily the stock mechanical components can handle the extra boost (from where most of the turbo's extra power readily derives), the greater the potential of aftermarket tuning to reliably increase power. 
