Quality has nothing to do with where a product is made. One can have low quality products made in the USA or high quality products made in Mexico. It has to do with what the manufacturer is willing to pay the build house and what they're willing to pay for materials. Moreover, a manufacturer can buy designs from a build house or it can spec them. I would assume that GZ specs them, hence the phrase "German Engineering".
It never ceases to amaze me that people automatically think that because cheap products come from China, all products that come from China are cheap. If that logic were sound... then ALL Americans are criminals, because America has the highest incarceration rate in the world.