I've seen stickers for German performance parts (neuspeed, etc) on Hondas.
Now that I'm a Saab person, I picked up a few of these stickers. I haven't gotten up the nerve to put them on my car yet.
Although I've only owned a Saab for 5 months, I already feel like a part of the community. They are a great bunch of people. Most of their cars are Saab 900 and 9000 which look completely stock (and old), but can keep up with/outperform my Viggen.
See some pics I took at the last two Saab runs. There is another show this weekend in Boston I will be attending.