Given the fat the the wheel positioning sensors for PSM are shared with ABS I imagine this is flashable? If I owned a GT2 i would strongly consider this complete with PSM dash buton.

 

you will need to add the rest of the parts needed. The booster pump for the brakes and I at least one or two other sensors

 

Its not needed... I AM PSM !! lol

 

 

F PSM...............

But an interesting question none the less

 

PSM is a sad and pathetic substitute for actual driving talent..

 

a interesting question....first you need a complete abs/psm hydraulic unit from a 996 tt (may be 996 carrera2 abs/psm is possible but realy dont know it)
the gt2 has a abs 5.3 without psm and the 996tt a 5.7 abs w/psm......

the next question is work the gt2 software dme with the psm?

i go a other way to have a usable first gear/ i have a reducuced boost only in 1. and 2. gear.../or switchable in all gears

 

Quote from my answer to question how PSM's have evolved:

First turbos used different Drehratensensor ie. "Yaw angle" sensor, which only communicates with certain ABS/PSM unit. Bosch brought a new sensor to MY '02 and works with all ABS/PSM units since. The programming is the same, or at least if you replace malfunctioning '02 unit with '04 unit it's just told if it's in tiptronic or manual car. Wiring looms are identical.
Carreras with PSM's work evolved similarily, first C4's got PSM '99 and that 1st gen unit/sensor set was used until '01. '02 it was replaced with 2nd gen.

And there's one more thing, 2WD Motronic requires a 2WD PSM unit and 4WD Motronic a 4WD unit.

So how I see it is that to get a PSM installed into a GT2 you would need to get a wiring loom from a turbo ( because there's no wiring for yaw angle sensor in non-PSM car ), turbo's Motronic ( GT2 engine programming is possible to do into a Turbos' ECU, but PSM into GT2's ECU may be impossible ), an ABS/PSM 5.7 hydraulic unit from a 4WD car, booster pump for PSMand a corrcet yaw rate sensor.
Unless you do all installation yourself it would cost big money.