I plan to make chili this week and I like to serve it with sour cream and cheddar. Two questions:

1. what is the right substitute for sour cream here? I've seen arguments
for both creme fraiche epaisse and quark. Keep in mind I want this to go on
my hot, spicy chili.

2. where can I find good cheddar in Lausanne? I bought something labelled
cheddar at the coop and it was hideous. (In North America I prefer the Canadian Black Diamond cheddar, if anyone knows that.)