A good combo I used to use on a black Cayenne was Klasse All-In-One base followed by P21s Carnuba wax and then topped off with Duragloss Aquawax spray. The Aquawax spray can be applied to a wet car before drying. I used to only then have to clay the car once a year and reapply the Klasse once a year. The P21s would be done 2-3 times a year and the Aquawax got sprayed on about every other week.
I'm getting older and lazier so now I am trying Ultima Paint Guard Plus. It is a nano-style wax that has a base cleaner followed by a wipe on spray wax. I put it on my 01 Silverado which gets washed maybe twice a year at best and the Ultima literally will not let any dirt stick to the paint - a simple handwash will get back to mirror smooth paint.