... GM and VW are the top selling brands in China ...
I rest my case. 
The argument that VW is not a "quality" brand is just not true, unless you consider "quality" based
solely on reliability. The fact is, VW competes more with Acura and Volvo than Honda and Toyota anymore. VWs are fancy vehicles, not the ultra-spartan transportation appliances you would expect in a Communist country.
As for GM, I know both Buick and Cadillac have Chinese-market cars that are as nice or nicer than their North-American counterparts (Cadillac SLS, Buick Royaum). According to Wikipedia,
Buick is China's best-selling automaker, with a lineup that includes the aging-but-affordable Regal, the LaCrosse (Allure), and the Royaum (aka Holden Statesman from Australia).