Mahle sounds good but keep in mind they have 160 plants world wide including 33 in China.
China has an operational Space Program unlike a lot of other countries - their manufacturing is amongst the best in the world so the location of the Mahle plant does not matter.
Consider that Lockheed and GM are both in the US, one of them makes gold and the other makes junk so the country in which the factories are situated is not relevant, it's about choosing the right company irrespective of what country you're in.
There are manufacturers in China that make junk, but there are also lots of cars being manufactured in China - most of the car comapnies we are familiar with have manufacturing in china and so need access to components - they take their pre-existing contracts and renegotiate to get the same suppliers and the same goods at their new location.
Unless you are building an extreme-use racecar, Mahle will do you proud with rings and shells.