I got quite a big interest in anthros, and ferals as well for that matter.. So yeah, I should be a "true" furry.
For the poll, I'd most likely wear just the tail due to not owning a fursuit.. however, I believe I'd rather consider a partial suit over a full one.
Other more 'extreme' and unrelated stuff I do includes believeing that I have a "inner fox" or at least have some sort of connection to canines, more specifically the fox, in general. I do wear a collar and I do tend to make quite a few animal-like noices to express myself. I do also, rarely but sometimes, use said noices over words since I feel it's easier for myself to express myself with a specific noice instead of explaining in words, even though not everyone always understands me. I have however on done that with people close to me... which is pretty much only my family and mate.
I do not believe the latter more 'extreme' stuff I just mentioned however is what makes you a furry. The only true definition of a furry is someone interested in anthropomorphic creatures, usually 'furry' art and of course not only the mature art! However, you don't have to be a furry just for being interested in it, if your a furry or not in in my opinion completely your choice, some people take part in the fandom only for being a part of the community while others take it even further than I do! It's really your own decision.