This vibration that you speak of, between 1900-200rpm, I experience it also yet strangely mine is the CVT automatic. From what I've read and seen, I believe it is MUCH more pronounced in a manual but I definitely feel this symptom to an extent. I usually notice it because the CVT likes to sit around 1900-2000rpm when setting off and for some annoying reason this rpm range creates a resonance that seems to make a buzzing noise. I'm not sure where the noise comes from as I have prodded everything