I'm a little late to this one.
I've owned German cars, Made in Germany, Mexico and Brazil. And multiple cars from each country. Honestly the best car I've owned are the ones put together in germany. My old MKIII made in mexico was pure garbage, just like my Jettas made in mexico. Pure cheaply made crap, they sounded like tin cars. My wolfsburg Jetta was amazing.. HUGE difference, my MKVI GTI made in Germany amazing.
I'm sure some good cars come out of the Mexico plant, but it seems like more Garbage comes out of that plant than good ones!
IMHO a german car should come from Germany!
This is not directed completely at you, but rather these posts about the quality of the car being based on the point of assembly. If a car sounds like a tin can and has cheap plastics, etc, that has very very little to do with point of assembly, but rather the engineering, and ultimately the budget of the build.
I think many people are missing the cause and effect here. The VW's coming out of mexico may well have been inferior, because they were constructed using inferior materials to cut costs, which is why they were being assembled in mexico to begin with...cheaper labor costs. Basically, the bean counters got greedy, and where not happy to stop at cheaper labor costs, and decided to cut into the cost of the materials and construction of the vehicle itself.
Are there some bad engineers? Sure, but most of this stuff comes down to budget constraints, especially the fit and finish of a vehicle, which is what most people notice.
Bottom line, if you take the exact same parts, send some to an assembly line in Wolfsburg, and some to an assembly line in Mexico, I doubt anyone could pick which car came from which with any kind of reliability.