They are partially correct. Using a circular high speed sander (the choice of professionals) can burn your paint if held in place and pressure applied. That is why most home detailers use a dual action orbital polisher like the PC. I recommend you watch the Meguiars Power Polishing Clinic video, which tells why it is easy, fail proof and superior to hand waxing. It also describes the correct way to use the polisher.

Assuming your car has no major blemishes, wash it, clay it, then polish with Meguiars Swirl Remover using a Green Giant Polishing Pad for German Vehicles and wax with Yellow Carnuba using a Red Concourse Finishing Pad.

Regarding Zymol... it is without a doubt good... but you better not let it dry or get it on an rubber pieces or you will be sorry.