Replacing broken tweeters from Bose 201 serie IV speakers


Hi! :)
The guy at the local speaker repair store told me the tweeters in my speakers need to be replaced and recommended me that I look online for them. I've looked everywhere for Bose tweeters that are from the same model (201 Serie IV 8 ohms) or at least the same size (2 3/8") and I can't find anything. Were do you guys look online when you need replacement parts such as these? Also, it is ok if I find tweeters that are the right size but from a different company? Are tweeters standard other than the fact that they have different shapes? Thanks!!!
monaeva