In 1980s, I wrote letters to car companies (no dealer in China at that time), then I can have some brochures from there - they usually liked to send me.
Now, I email some car companies out of China, some of them can send me, and some of them give me PDF - I hate PDF! Main way for me to have brochure is from other car brochure collectors all around the world.
Here is the link about world car brochure collectors:
http://www.carsonpaper.nl/collectors.htm