Behr, Wahler, and European aftermarkets will probably be fine. I'd be more concerned about the chain store thermostats. Usually don't have the correct bleed valve, and if they do sometimes it's in backwards. They can also have the wrong amount of travel for the back flap, and you won't be able to tell by looking.

Nothing against aftermarket parts, sometimes they are better, but American manufacture aftermarket thermostats for European cars can be a problem.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!