It does not have an official limit set but in reality it is limited by the time allotted for production (short) and the capacity to make a complex car like it.

Rumors (a friend of a friend knows someone who has a friend who heard from a neighbor of some Porsche employee) swirl around with numbers from a 1000 to 3000 but if the factory announced an official limit of lets say 2000 units everyone would all over it as the next coming.

In US at least , if you really want it you can have it but it will cost you at minimum what the R was going for recently.