[Germanauto]

Have only been to forums of similar luxury makes and found that none of them are as active as Bimmerpost. This is the strongest enthusiast community because BMW is an enthusiast brand! I can't speak much to Porsche (Rennlist?) but I'd suspect their community is active but comprised of an older demographic and not as fun to be around.

Reddit (r/cars) is the other main site I hit up as it's always very active. There as some fun threads but a lot of BS as well. It's a diverse community so there's a ton of arguments.