Nope, cant layer a polymer over a wax. Some feel thats a good reason not to top klasse (or any polymer) with a wax, but feel it works out great. I usually have time to apply 2 SG (with 12-24 hours in between). The great thing about some good polyners, klasse, zaino ect is that they retain their shine very well, much better than a wax. So i find that there is no real need to keep applying more SG because w/ two coats and a wax topper, it can last you a good 12 moths, and its recomended to mildly polish your paint once a year so youl just be removeing the layers of SG anyway. A wax on the other hand shoud be reapplied every two months or so, which brings back that wet look on top of the klasse. Now i just made everthing complicated so back to the origional question, no you cant top a wax with SG, but i wouldn't worry about not being able to anyway.