Do you want this if you track your car regularly?

And also..the 20 inch wheels?

 

a clear YES, cause Torque vectoring is made for better cornering and that´s what a track is about, or not?!
It allows you to go into corners almost without needing to use steering and braking. The computer does it for you with precision. Together with the limited rear slip differential you get the best traction and therefore greater agility and better handling in corners and it also provides more stability(+safety) and less oversteer, cause the car is less sensitive to load changes too.


as far as 20" wheels are concerned:
less unsprung mass wheels = better for the track

but as Tech1_Mike said on another 991 thread:"The 20 inch Wheel and Tire package will likely be very close in weight to the 19s. We found the same with the 19/18 comparison. The 18 inch wheels are lighter but the tires are heavier. It is actually not difficult to make a 20 inch wheel setup weigh the same as the factory 19s."

so the weight of a 20" set up should not be too much of an issue (as long as you are not participating in races, in which every single g counts.)
and comfort isn`t that important on a track as well.

 

OK.

will the PTC system under heavy track use lead to more brake and tire wear?

 

What PTV does is, it gives the car more stability, more lateral grip, and the driver more confidence to explore the limits, which are higher than on conventional machines. the car is more balanced in all situations, less energy is wasted, which leads to less tire and brake wear.
But to significantly less? i doubt that, esp. in heavy track use.

P.S. PTV pushes the driving limits further, that´s the real advantage of the system.
hard driving will always kill brake(pad)s or tires, with or without PTV.