I finally just have used the German detailing product , Klasse. I have to say, it is a class product. Ist, the red bottle is a cleaner/protector. The goes on and comes off easily like Autoglym Super Resin Polish. Then, the silver bottle. This is sealant glaze. It is acrylic and if put on too heavily and left for too long, it needs the sort of effort for flatting paint. In fact, on my sister's 155, I could actually see the depth of coat it left on the paint as it was put on quite thick (by her).
Anyway, after she used it a year ago, it was still evident just how much easier her car was to clean, and how smooth the paint still was. Ok, her car was de-nibbed with a clay bar before, but 12 months on, and it was still noticeable.
Back to today. I went over my 156. A few months ago, I machine polished it. Lately, I have been using the clay bar on it, and now really going to town with this Klasse.
I will still finiish it with a wax (Zymol of course), because I've heard that although shiny, the Klasse finish is a little artificial to the connesseur. For everyone else, it is a very durable shiney protector which is generally not too much effort and actually quite ecomonical to use.
I'm not really a polisher, and use my car- quite hard on occasion and with particluar note of trackdays. All I wanted was to be able to have long lasting protection so that weekly upkeep and cleaning is easier- because I'm a lazy git.
BTW, I'm impressed by this product.

Although it costs a bit, I think that the two bottles should last a car 3-5 years depending on use and frequency of re-application.