I Got a Cayenne done in August 2018 with the full Gtechniq package (think it cost 1,800 - I didn't have to pay as a builder sprayed concrete on the car)
I have to say I am still very happy with it, swirling is minimal and when clean the shine is unreal - It still does get dirty especially in this weather but washing it properly means it stays cleaner longer. The exo has faded so will probably do that myself next summer but the underlying coating seems to be doing what it says it should.