I own a 2017 Q5 which I purchased new back in December 2016. After I purchased the vehicle I clayed the entire car and applied Sonax Polymer Net Shield sealant. My Q5 spends most of the time in the garage and the shine is still terrific and the water still streaks right off. Since it has been two years since I've applied the Sonax I'm thinking it should be time to apply another coat. I was planning on claying the car but not sure if I should just apply another coat of Sonax PNS, or should I use a very mild polish before applying the PNS. I can not believe how great the Sonax PNS has held up, granted the car is always garaged, but it has gone on its share of pretty long road trips. Thanks.