Here at DCist, we deliver. We’ve gotten potholes fixed, and now we’re getting new speakers put into Metro stations. Well, that’s a slight exaggeration. Ok, a total exaggeration. But that’s neither here nor there. Today Get There, the Post’s transportation blog, reports that Metro is in the midst of a three-year, $18 million project to replace the system’s crappy PA system. After hearing one too many garbled messages concerning safety or service changes earlier this…